Mammography and the acute discomfort of change

As I write this, I am attending the 2014 meeting of the American Association for Cancer Research (AACR, Twitter hashtag #AACR14) in San Diego. Basically, it’s one of the largest meetings of basic and translational cancer researchers in the world. I try to go every year, and pretty much have succeeded since around 1998 or 1999. As an “old-timer” who’s attended at least a dozen AACR meetings and presented many abstracts, I can see various trends and observe the attitudes of researchers involved in basic research, contrasting them to that of clinicians. One difference is, as you might expect, that basic and translational researchers tend to embrace new findings and ideas much more rapidly than clinicians do. This is not unexpected because the reason scientists and clinical researchers actually do research is because they want to discover something new. Physicians who are not also researchers become physicians because they want to take care of patients. Because they represent the direct interface between (hopefully) science-based medicine and actual patients, they have a tendency to be more conservative about embracing new findings or rejecting current treatments found not to be effective.

While basic scientists are as human anyone else and therefore just as prone to be suspicious and dismissive of findings that do not jibe with their scientific world view, they can (usually) eventually be convinced by experimental observations and evidence. As I’ve said many times before, the process is messy and frequently combative, but eventually science wins out, although sometimes it takes far longer than in retrospect we think it should have, an observations frequently exploited by advocates of pseudoscience and quackery to claim that their pseudoscience or quackery must be taken seriously because “science was wrong before.” To this, I like to paraphrase Dara O’Briain’s famous adage that just because science doesn’t know everything doesn’t mean you can fill in the gaps with whatever fairy tale that you want. But I digress (although only a little). In accepting the validity of science that indicates either that a medical intervention that was commonly used either doesn’t help, doesn’t help as much as we thought it did, or can even be harmful, they have to contend with the normal human reluctance to admit to oneself that what one was doing before might not have been of value (or might have been of less value than previously believed) or that, worst of all, might have caused harm. Or, to put it differently, physicians understandably become acutely uncomfortable when faced with evidence that the benefit-risk profile of common treatment or test might not be as favorable as previously believed. Add to that the investment that various specialties have in such treatments, which lead to financial conflicts of interest (COI) and desires to protect turf (and therefore income), and negative evidence can have a hard go among clinicians.

Examples abound in the history of medicine. In my own specialty, some surgeons resisted the transition over to doing needle biopsies of breast cancers because that meant more radiologists and fewer surgeons would be doing breast biopsies. There was also resistance to the concept that doing only partial mastectomies (“lumpectomy”) was safe and effective. Urologists weren’t too thrilled with the development of drugs that could shrink benign prostatic hypertrophy (BPH), the proliferation of which resulted in a dramatic decline in the number of transurethral resections of the prostate (TURPs) performed. The proliferation of angiographic stenting of coronary blockages led to turf battles over which lesions needed surgical bypass and which ones could be safely stented by cardiologists. Tonsillectomy is another good example of a procedure that was widely done (I had one when I was around 6) but now seldom done because in the vast majority of cases before it was unnecessary.

All of which brings us to screening mammography, in my usual meandering way, because there were two new studies from JAMA last week that add to the drip, drip, drip of mammography studies that all seem to be converging on similar conclusions. Once again, I must emphasize that I am not talking about diagnostic mammography; i.e., mammography ordered to evaluate a lump or other symptoms in the breast. Nothing—I repeat—nothing has changed with respect to that. If a woman has a lump in her breast or concerning symptoms, mammography is indicated. What I am referring to is screening mammography performed on women without symptoms in order to detect breast cancer before it becomes symptomatic. I cannot emphasize that enough.

Yet another mammography study…times two

Last week, as has been happening more frequently, there was a study published that cast more doubt on current mammography guidelines. It is not like the Canadian National Breast Screening Study whose results were published a couple of months ago in that it does not find that screening mammography does not result in a benefit. However, it does find that the benefit-risk ratio of routine screening mammography is not as favorable as believed in the past. Rather, it is more like studies by Gilbert Welch, a Norwegian study, and studies highlighting the problem of overdiagnosis, in which significant percentages of screening-detected cancers are overtreated and some even spontaneously regress. Before I get to the study itself, I often like to give you a flavor of how the press reported the study. An example of pretty good reporting is the news story from NPR covering the study.

Here’s the study by Lydia E. Pace and Nancy L. Keating, entitled A Systematic Assessment of Benefits and Risks to Guide Breast Cancer Screening Decisions. It’s not behind a paywall, indicating that JAMA must have thought it important enough that it should be widely available. It’s also pretty well written and (mostly) understandable, even if you don’t necessarily have a high level of expertise in mammography and epidemiology. What the authors did was to search MEDLINE for relevant randomized clinical trials (RCTs), meta-analyses, systematic reviews, and observational studies from 1960 to January 19, 2014, as well as the references of key articles, reviews, meta-analyses, and practice recommendations, which were searched manually. They also included meta-analyses of randomized clinical trials (RCTs) of mammography screening examining breast cancer mortality. From 525 articles identified, 20 meta-analyses met these criteria, and the authors, quite appropriately, focused most of their attention on the 5 meta-analyses published after 2006, which include the last RCT of mammography.

Another thing that the authors did was to emphasize their estimates of number needed to invite (NNI) to screening, as well as absolute risk ratios. Frequently, results of clinical trials (not just RCTs of mammography) are presented as relative risk reductions (e.g., “mammography decreases the risk of dying of breast cancer by 19%), which can be misleading if the absolute risks and risk reduction are low. I’ve described this phenomenon before in the context of RCTs of adjuvant chemotherapy for breast cancer, where a 30% relative risk reduction might actually mean only a 2-3% absolute decrease in the risk of dying of early stage breast cancer. In adjuvant chemotherapy for breast cancer, the absolute magnitude of the survival benefit increases along with the absolute risk of dying. In other words, a given adjuvant chemotherapy regimen might produce a similar, say, 30% decrease in the risk of dying for all breast cancers of a certain subtype, but that 30% means more on an absolute basis for nastier tumors. Put it this way. If you have a 50% chance of dying of your disease, a 30% relative risk reduction of that risk translates to a 15% lower chance of dying on an absolute basis. If, on the other hand, you only have a 10% chance of dying of your disease, that same 30% relative risk reduction translates to only a 3% absolute risk reduction.

A similar principle exists for screening tests, and this review explains that quite well, boiling it down into a couple of concise tables. Since the article is free, I don’t feel obligated to reproduce Table I and Table II so I’ll just discuss them. Table I shows pooled mortality reductions due to mammography for different age ranges. I could discuss how the authors derived their estimates ad nauseam. Certainly, if anyone wants to get into that level of detail, he’d have to have a detailed understanding of the studies that went into coming up with these numbers. Given that the numbers are roughly consistent with estimates that Laura Esserman derived in her review and a fair number of other estimates, I’ll spare you. Basically, Table I was derived from Nelson et al., the meta-analysis conducted for the USPSTF. The key parts of the estimates is this: The younger the patient group, the higher the NNI is, ranging from 377 for women aged 60-69, resulting in an absolute risk reduction of dying from breast cancer in the next ten years of approximately 0.3%, to 1,904 for women aged 40-49, translating to an absolute risk reduction of 0.05%.

Table II shows the estimated benefits and harms of screening mammography for women in the various age ranges studied for 10,000 women undergoing screening using Surveillance, Epidemiology, and End Results (SEER) estimates from a recent review by Welch and Passow. Not unsurprisingly, the error bars are large. The lower number reflects a minimal breast cancer mortality of 5% based on RCTs reporting no benefit, while the upper number reflects a reduction of 36% based on the clinical trial reporting the highest benefit, the always-cited Swedish trial by Tabár et al.

Also included are estimates of overdiagnosis, false positives screening studies requiring more imaging and/or biopsy, and the number of patients who underwent one or more unnecessary biopsies during the ten year period. Again, the numbers for overdiagnosis are similar, actually slightly lower, than the numbers I’ve discussed before, which have generally converged around an estimate of 20% or slightly more of screen-diagnosed breast cancers turning out to be overdiagnosed. I note that in all age ranges the upper estimates of overdiagnosis approach 40% but that in women aged 40-49 the upper estimate is over half. For women starting screening at age 40 or 50, the chance of at least one false-positive result is 61%, while it’s 49.7% for women undergoing screening between the ages of 66 and 74.

These results lead the authors to conclude:

Although some of the challenges of mammography can be resolved with further research to guide individualized decisions and thoughtful development and dissemination of decision aids, better breast cancer screening tests are needed. More sophisticated tools, for example, could distinguish aggressive vs indolent tumors, reducing the burden of overtreatment.86 Mammography screening appears to be associated with reduced breast cancer mortality, but for some patients, the harms may outweigh the benefits. Until better screening methods are available, improved understanding of these harms, enhanced strategies to identify the highest-risk patients, and tools to help patients and clinicians incorporate these in their decisions should be research priorities.

Or, as one article reporting on the study characterized it, Stop One-Size-Fits-All Mammography. This is a reasonable take-home message from the study. The problem, of course, is that our risk assessment tools and models are still, even a decade into the genomic revolution, grossly inadequate to the task.

Adding to the confusion is a review article that appeared in the same issue of JAMA by Louise C. Walter and Mara A. Schonberg, entitled Screening Mammography in Older Women: A Review. It begins with a patient story:

Mrs M is 91 years old and has had annual screening mammograms since age 50. She lives alone in her apartment and independently performs all activities of daily living. Her chronic medical conditions include hypertension and osteopenia, and she was diagnosed with intermittent claudication in 2010. Her medications include valsartan, furosemide, and isosorbide dinitrate. Mrs M had her only child at age 16, experienced menopause at age 50, and never used postmenopausal estrogen or progesterone. She had a negative breast biopsy in 1984. Her daughter died of breast cancer at age 37.

In 2008 at age 87, Mrs M had an abnormal screening mammogram with microcalcifications in the left medial inferior breast, interpreted as category 3 (Breast Imaging-Reporting Data System [BI-RADS]; probably benign). She subsequently underwent scheduled 6-month follow-up diagnostic mammograms over the next 18 months. The third mammogram, performed in 2010, showed interval increase in the number of heterogeneous microcalcifications and was classified as a BI-RADS category 5 (highly suggestive of malignancy). The lesion was not amenable to biopsy under stereotactic guidance. Therefore, she underwent excisional biopsy of the left breast lesion using needle localization. The biopsy identified ductal carcinoma in situ (DCIS), intermediate grade without comedo-type necrosis, on 2 of 9 slides. Estrogen receptor staining was strongly positive. One area of DCIS was less than 1 mm from the anterior margin so she underwent reexcision and no residual DCIS was identified. Mrs M met with a radiation oncologist who did not recommend radiation therapy, and she declined tamoxifen due to concerns about adverse effects. She continues to undergo annual mammograms, which have been negative, and she is seen by a breast oncologist every 6 months.

Mrs M: I get mammograms every year. I know you don’t get them all your life.

Dr P: I think people might say: “What are you doing getting mammograms in a 91-year-old?” but you have to meet this lady. She is a lot more likely to live to be 100 than I am.

It might be surprising to you, but there are no RCTs examining screening mammography that included women over 74. All the major studies that showed a decrease in death due to breast cancer in women screened by mammography excluded older women. Most guideline panels and organizations have therefore recommended that screening mammography in women 75 and older be decided based on an individualized approach that weighs potential benefits and harms of screening in the context of a woman’s overall health, life expectancy, and preferences. It’s a shocking hole in our evidence base with regards to screening mammography, but there it is. Clinicians, as is so often the case, have to apply an incomplete data set lacking rigorous studies to individual patients.

To examine the issue of mammography in women 75 and older, the investigators attempted to look at the balance of risk and benefit in such women. It’s not just a woman’s risk of breast cancer, as in the first study, that drives the risk-benefit consideration. It’s also how long a woman is likely to live, which drives the risk that a women will (1) develop breast cancer in her lifetime and (2) that that breast cancer will kill her before something else does, such as old age. The authors therefore searched PubMed for English-language studies in peer-reviewed journals published from January 1, 1990, to February 1, 2014, to identify risk factors for late-life breast cancer in women aged 65 years and older and to quantify the benefits and harms of screening mammography for women aged 75 years and older. Their first search identified 864 articles, of which 24 provided data on risk factors for breast cancer in women aged 65 years and older. The second search resulted in 2,121 articles of which 13 provided data on survival benefits and/or false-positive results and biopsies following screening mammography specifically for women aged 75 years and older.

Their conclusions/recommendations from their review of the literature included:

  • Advancing age is the greatest risk factor for developing breast cancer. Risk factors that reflect hormonal exposures in the distant past (eg, age at first birth, age at menarche) may be less predictive of late-life breast cancer than factors indicating recent hormonal exposures (eg, high bone mass or obesity).
  • Randomized trials of screening mammography did not include women aged 75 years and older. Observational studies suggest benefit of continued screening mammography in older women who have a life expectancy of more than 10 years.
  • Potential harms of screening mammography include overdiagnosis (ie, finding a breast cancer that would not have clinically surfaced in the absence of screening) as well as pain and anxiety associated with false-positive results and biopsies.
  • Breast cancer treatments are effective among older women in good health; however, the harms of breast cancer treatment increase as women age, particularly among older women with limited life expectancy.
  • Providing information about life expectancy along with potential benefits and harms of screening mammography may help older women’s decision making about screening mammography.

Regarding #4 above, the authors also note that screening women over 74 will only be effective if effective treatments exist for early stage aysmptomatic breast cancer in such women. Unfortunately, few breast cancer treatment clinical trials included women aged 75 years and older or women with multiple comorbidities or frailty. In other words, not only are women older than 74 not represented in RCTs of mammography, but they are underrepresented in RCTs testing breast cancer treatments. Indeed, women 65 and older are grossly underrepresented in breast cancer clinical trials. Confusing things even more is that breast cancers diagnosed in older women tend to more indolent tumors, exactly the kind that are more frequently overdiagnosed, thanks to length bias. Thus, overdiagnosis tends to increase with age, both because older women tend to develop more indolent tumors and, to put it bluntly but very simply, there’s less time for diagnosed cancers to kill them. This led to an estimate by the authors that roughly 32% of breast cancers diagnosed by screening mammography in older women will be overdiagnosed.

Overall, the authors’ recommendations are reasonable, but, as is the case in the first article, maddeningly vague, leaving the primary doctor to do pretty much what he or she thinks is best, with little hard guidance as to what is best. Overall, however, adding these two studies to the pile of studies that have been published over the last six years or so, I am definitely coming to agree with Pace and Keating that the era of one-size-fits-all mammography is almost certainly coming to an end. Indeed, even the Komen Foundation seems to recognize this in its statement about the first study. If you read it, you’ll notice a subtle backing-away from a concrete recommendation that screening begin at 40, with a shift in emphasis towards the need for better tools to evaluate a woman’s risk of breast cancer to guide screening decisions. To that I’d add that we desperately need better tests for diagnosed cancers and DCIS, in order to determine who does and doesn’t require aggressive treatment.

In the meantime, however, clinicians are left with uncertainty, and clinicians, understandably, don’t like uncertainty.

Putting it into context

Being a translational researcher in addition to a surgeon, I’m a bit “schizophrenic” in that I live in both worlds, the world of the clinician and the world of the basic/translational scientist. Because until relatively recently I didn’t do much clinical research, I tended to think much more like a basic scientist in some areas but, when it came to routine practice, I thought much more like a clinician. So it was that I didn’t think much about the guidelines for mammography until around six years ago or so. The guidelines were the guidelines, and I followed them, not really showing much interest in the science behind them. Then in 2008, I rediscovered the concept of overdiagnosis, something that doctors tend not to be taught about as much as they should be and therefore something that they either know little about or tend to dismiss. The result was my first post about how difficult it is to show that early detection of cancer results in improved outcomes, thanks to the issues of lead time bias and length bias. Then in 2009, I noted a review/commentary article by Laura Esserman regarding the need to rethink how we screen for breast and prostate cancer, highlighting the high numbers of people who need to be screened to prevent one death from the cancer screened for and the not inconsequential harm of overtreatment that can occur.

It seemed like karmic justice that two weeks later the United States Preventive Services Task Force (USPSTF) published its suggested guidelines with regard to screening mammography, in which it recommended that screening begin at age 50, not 40, and that it be conducted every other year rather than every year. I commented on the guidelines, of course, noting that they were not the final word, a prediction about as safe as predicting that the sun will rise in the east or that this year’s election will be contentious. It was also my first acutely-uncomfortable experience with new findings regarding mammographic screening, as I found myself in the distinct minority among my colleagues in not being alarmed by the results or feeling the need to explain them away. Worse, this was the first time that I had ever been in any sort of position where I was asked to help craft the official public response by my cancer center, a task that had to be completed within a day or so because of the number of inquiries we were getting. It was my first real experience trying to communicate science in a way that had real consequences. Blogging is just blogging, and I can spout off more or less what I’m thinking without worrying overmuch about it. In contrast, this time, I was trying to help craft a statement as part of my real world job, a statement that could have real effects on patients.

The reason it was so hard is because over the years the guidelines that stated that screening mammography should start at age 40 and be done yearly had become very entrenched, and persuading women that this was a good thing to do required a simple, concrete message. The USPSTF guidelines laid bare in a highly publicized story how messy the scientific process and, in particular, the process of translating basic and clinical science into guidelines is. Predictably, cancer quacks seized on these guidelines that “mammography doesn’t work,” while advocate groups were dismayed and had to defend their guidelines, while some radiologists used what can only be described as despicable claims to protect their turf (and still do).

It’s instructive to look at what the American Cancer Society has recommended over the years, which is conveniently found in a table form on the ACS website. It wasn’t until 1997 that the ACS started recommending yearly mammography for women between 40 and 49. Before that, the recommendation was for a baseline mammogram at or around age 40 and then mammography every 1 to 2 years. Before that, the recommendation was for a woman to consult her physician, and before that the recommendation was: “May have mammogram if they or their mother or sisters had breast cancer.” This occurred not long after two other occurrences. First, there was an NIH consensus conference on mammography in women aged 40-49 held earlier that year.

The press release about that conference and the controversies discussed sounds eerily familiar to much of what I just discussed above. Second, the National Cancer Advisory Board recommended “that the National Cancer Institute (NCI) advise women 40 to 49 to get screening mammograms every one to two years if they are at average risk for breast cancer.” Interestingly, no mention was made of overdiagnosis and overtreatment; the only harms listed were false positives, which, it was noted, are more common in younger women. The NCAB also notes that its decision reversed a previous decision in 1993 to withdraw its recommendation for routine screening mammography between ages 40 and 49. Not coincidentally, the NCI reversed itself less than a week after the ACS and American College of Radiology (ACR). Although the NCI denied that its decision was influenced by it, there was intense political pressure brought to bear, with the Senate previously having unanimously passed a resolution urging mammograms for women in their 40s. In addition, Sen. Arlen Specter, R-Pa., had threatened the NCI director’s job over the controversy, as his Senate subcommittee that oversees federal health spending practically ordered the NCI to do the same, and several legislators wrote or called the NCAB with the same request.

In other words, everything old is new again. Most people aren’t aware of the long strange trip mammography took to become what it is now. Politics has been and continues to be a factor in determining mammography guidelines.

Of course, the American College of Radiology, as has been the case every time a study has been published that found that either the risks of mammography were higher than thought before or the benefits not as great as previously believed, is at it again, this time with the Society of Breast Imaging. The two professional societies issued a joint press release last week, and it’s full of the usual spin:

The American College of Radiology (ACR) and Society of Breast Imaging (SBI) agree with statements made by Pace and Keating, in their recent article published in the Journal of the American Medical Association (JAMA), that women should discuss mammography with their doctor and breast cancer diagnosis and treatment may one day be more individualized. However, at present, breast cancer screening based primarily on risk — as discussed in the JAMA article — would miss the overwhelming majority of breast cancers present in women and result in thousands of unnecessary deaths each year.

Utter piffle, so much so that another post might well be required to explain why. Suffice to say that the press release trots out the same tired (and discredited) arguments that somehow the CNBSS has been “discredited” (it hasn’t) and a paper purporting to show that overdiagnosis is not nearly as big a problem as recent studies have indicated, which might require an entire new post of its own. In the meantime, suffice also to say that there’s less to the attacks on, for example, Bleyer and Welch’s study from 2012 than certain radiologists would like you to believe.

What to do?

Contrary to the hysterical denunciations of the recent studies that have led me to this conclusion, women won’t be dying in droves if screening recommendations are made less intense. Most developed countries don’t start screening until age 50 for most women, and most only recommend biennial screening. Yet, these countries have breast cancer mortality rates comparable to what is observed in the US. That means one of two things: Either Europeans have better treatments for breast cancer than we do, sufficient to compensate for later diagnosis due to less intensive mammographic screening, or starting screening at age 50 doesn’t detectably affect mortality from breast cancer compared to starting at age 40. I doubt that Europeans have treatments for breast cancer that are that much better than those in the US; the second explanation is more likely the correct one.

As a surgeon and a scientist, I’ve found the resurrection of the debate over the efficacy of screening mammography to prevent breast cancer deaths to be simultaneously frustrating, educational, and confusing. I also realize that, although I specialize in the surgical treatment of breast cancer, in a way I’m not “on the front lines” in that I don’t see a lot of healthy women and advise them about whether to get their yearly mammogram beginning at age 40 or not. By the time they see me, they either have breast cancer, a suspicious lump (which means they will get more imaging if they haven’t already had it) or a mammographic abnormality that can’t be needle-biopsied and needs a surgical biopsy. That being said, as hard as it is for me sometimes to believe, I have served as leader of our breast cancer program and still work closely with existing leaders. I cannot avoid “taking a stand.”

Until recently, my stand was that we should stick with the existing guidelines until our professional organizations can examine the science and come up with new guidelines that reflect more recent studies. However, more and more I am of the opinion that we do over-screen. I still believe that mammography is of benefit in women of average risk beginning at age 50, but I’m becoming much less convinced of its utility in women under 50, at least those without identifiable risk factors for breast cancer. Such women should indeed have an individualized approach to screening. I say that, even though I recognize that our currently existing tools are grossly inadequate to give any more than a rough estimate. However, I also recognize that part of the equation has to be an accurate understanding of the absolute numbers and what the individual woman being screened values.

What that will mean remains to be worked out. Again. And the process will be messy. Again.

Posted in: Cancer, Diagnostic tests & procedures, Public Health, Science and the Media

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55 thoughts on “Mammography and the acute discomfort of change

  1. Bidan Nancy says:

    Advancing age is the greatest risk factor for developing breast cancer. Risk factors that reflect hormonal exposures in the distant past (eg, age at first birth, age at menarche) may be less predictive ==> I don’t really get it.

    Firstly, there are a lot of old women out there who didn’t get any breast cancer at all, while the younger women struck by the deadly disease.

    Isn’t lifestyle a greater risk than simply aging?

    1. David Gorski says:

      No. It isn’t. Lifestyle, in fact, is a relatively weak risk factor for breast cancer compared to age and family history. It’s not even close.

      1. stanmrak says:

        How in the world can lifestyle even be scientifically measured… Who knows how many risk factors, such as toxins in the environment, and in the food, a person has been exposed to. Most of the 80,000 or so chemicals in our food have never been tested enough to guarantee they’re safe. There would be an infinite number of variables to work out to assess the true correlation. Impossible. I think this is just an assertion based on no real data.

        1. David Gorski says:

          Lifestyle certainly has been studied—and rather extensively for breast cancer.

          Diet has been studied, with conflicting results. (Fat intake doesn’t correlate, but obesity does.) Alcohol consumption has been studied. (There’s a modest, but convincing, correlation between alcohol intake and breast cancer, which was reinforced at a talk I went to yesterday at AACR.) Exercise seems to have a mild protective effect. Even so, if you add up all these factors, the effect of these lifestyle interventions is still considerably less than that of family history and aging.

          1. Schizodoc says:

            The great rise in breast cancer risk with age has yet to be linked with a specific feature of the ageing process, and it remains true that not all ageing women get the disease. One imagines that the up-curve of risk rises much more slowly in non-Western populations–or used to, before the toxic Western diet went global.

            My grandmother died a shocking death from breast cancer–screaming in pain and sleepless for days on end. Truly horrific for the family.

            The first suggestion of what might cause non-inherited cases seems to have come from epidemiology–e,g. Japanese women used to have a very low incidence, compared with Western women. The most obvious difference in diet was saturated fat intake, but only a small risk has been found with fatty diet–maybe a 30% increase, or none at all in some studies.

            Fatty diet [low ratio of polyunsaturated to saturated fat (and trans-fat)] is known to reduce cell membrane polyunsaturate content, resulting in insulin resistance and mitochondrial free radical production [superoxide and H2O2].

            This diet-related aqueous oxidation may explain the link between fatty diet and Parkinson’s disease [and also between PD and glucose intolerance]. Fatty diet is known to cause Type 2 Diabetes, too, in which oxidised DNA bases appear in the urine. Chronic oxidative stress may drive growth factor pathways, in addition to promoting oxidative DNA damage.

            Indeed, cancer risk is higher in diabetes, but I haven’t checked on breast cancer, in particular.

            More recently, an unexpected cancer risk has been identified in Western diets, that may have a much higher impact: total energy intake, and high animal protein intake, in particular.

            Cancer metabolism/glycolysis expert Dr Craig Thompson, at Sloan-Kettering, points out that cells in multicellular organisms are not autonomous–nutrient supply is constant, but active growth and proliferation only occur in response to growth factor and hormonal signals. Otherwise, most dividing cells would grab glucose and amino acids, and grow uncontrollably, so killing the organism.

            High energy intake may promote excessive cell growth and division, e.g. high glycaemic index carbs do seem to cause an insulin spike–which, alone, may cause [or allow] cells to take up both glucose and amino acids. In addition, insulin may down-regulate the production of binding proteins for Insulin-like Growth Factor 1 [IGF-1]. thereby increasing the blood level of unbound, active IGF-1.

            IGF-1, which rises and falls also with animal protein intake, has been called a One-Stop Shop for cancer–it drives fast cell division, reduces the time available to correct DNA damage in dividing cells, and prevents cell death of mutated cells [“anti-apoptotic” effect].

            See the latest on this high-energy intake/high animal protein intake story: Google or use PubMed, to find stuff by Dr Valter Longo [animal protein/cancer risk], Prof Bodo Melnik [high energy intake, mTORC1, leucine amino acid, whey peptides, cow’s milk growth factors, etc..].

            Chronic stimulation of mTORC1 activity [mammalian Target of Rapamycin Complex 1] which lies downstream of–and integrates– glucose metabolism, energy [ATP] production and IGF-1 signalling, specifically drives the expression of proteins involved in cell growth and proliferation.

            One would also expect a high-energy diet, especially one rich in leucine amino acid and dairy proteins/growth factors, to strongly promote bodily growth, early puberty, and sex hormone overactivity. Dr Melnik has related acne vulgaris and androgen sensitivity to mTORC1 activation, and one wonders whether a similar diet, in females, might drive oestrogen activity.

            Given the uncertain value of screening mammography, we should at least warn women to follow a much more “Japanese” type diet–low in animal protein and dairy peptides, and rich in phytic acid [in grains, nuts and legumes], which has broad-spectrum cancer-preventive properties.

            1. WilliamLawrenceUtridge says:

              The great rise in breast cancer risk with age has yet to be linked with a specific feature of the ageing process

              What, you mean aside from the inexorable number of copying errors in the cellular DNA due to the number of times the DNA is copied rising linearly with the age of the person? Yeah, except for that, there’s totally no link between age and cancer.

              People in the past got cancer. Some of our examples come from mummies of Egyptian pharaohs, who were wealthy and privileged enough to have more than adequate diets. Further, because of the volume of food consumed in the West, even allegedly “low quality” diets still contain considerable nutrients, more than enough for most to meet or exceed their RDIs, which in turn are set deliberately high in order to ensure the majority of people are guaranteed to get enough vitamins and minerals.

              and it remains true that not all ageing women get the disease.

              Not all people die of vaccine-preventible diseases, but we still vaccinate as universally as possible. Not all smokers die of lung cancer, should we remove warnings from cigarette packs?

              One imagines that the up-curve of risk rises much more slowly in non-Western populations–or used to, before the toxic Western diet went global.

              One might imagine this, that doesn’t mean it’s true. The Western diet is mostly associated with cardiovascular risks rather than cancers.

              Japanese women used to have a very low incidence, compared with Western women.

              Japanese women also tend to have much less breast tissue, and much higher rates of stomach cancer.

    2. WilliamLawrenceUtridge says:

      There are a lot of people who have lifestyle risk factors that also don’t develop cancer. The typical example of a lifetime smoker who dies in their sleep at 94 years of age being one of them. Or for that matter, those who do the “right” things but still die (i.e. Jim Fixx, though not the perfect example, is a salient one).

      1. stanmrak says:

        Jim Fixx certainly wasn’t exactly doing all the “right things.’ He assumed that exercise was all he needed to stay healthy. He didn’t just ignore expert advice that he needed to eat healthier, he went out of his way to criticize those who offered such advice. Fixx was seen to wolf down 4 doughnuts for breakfast one time as if it didn’t matter.

        Someone with a very similar early health history and risk factors was Jack Lalanne, but he lived to be 96. Of course, his diet was as important to him as exercising.

        1. Windriven says:

          “Fixx was seen to wolf down 4 doughnuts for breakfast one time as if it didn’t matter.”

          The bastard! Four donuts one time. It would have served him right to drop dead on the Timmy Ho’s floor*.

          You know stan, there are plentiful anecdotes of people eating, drinking and smoking with abandon and living to ripe ages. James Beard lived to be 82 and Julia Child into her 90s. These were people who ate well and troubled themselves little with exercise. The difference between us is that I am not holding up the gourmand lifestyle as a prescription for health and longevity.

          *For those who don’t know Tim Horton’s – affectionately known to youthful locals as Timmy Ho’s – is a terrific chain of donut shops in Canada. I don’t know that I’ve ever eaten 4 donuts at a whack but I’ve certainly eaten 3. Mostly I consume a reasonable diet of limited fats, plentiful fish and veggies, and probably an over abundance of carbs owing to an inordinate love of well-baked bread. If porking out on donuts a couple of times a year is going to buy me an express ticket to a cold hole, bury me with powdered sugar on my nose.

        2. Chris says:

          You do realize that this is about testing women who are at or older than the average lifespan in this country. One would assume that not dying young is part of having a good lifestyle.

        3. Chris says:

          “One would assume that not dying young is part of having a good lifestyle.”

          And additionally being in good health, as noted by the patient story about 91 year old Mrs. M in the article. My mother-in-law, who is a bit younger than her, is also in excellent health and probably has almost twenty years more of life in her.

        4. goodnightirene says:

          LaLanne’s brother lived to be about the same age and didn’t do those things. They had good genes. Fixx had a specific heart problem that (while I don’t recommend donuts for anyone) that puts him out of the “average” category.

          My neighbor is 92, still works in her yard and just quit driving last year–all this on a lifetime of white bread, margarine in tubs and all sorts of things like hot dogs. The important thing is that she always maintained a healthy weight and even now takes care to do so. She likes a donut now and then, too!

        5. WilliamLawrenceUtridge says:

          And thus stan misses my point – research and lifestyle factors on all health outcomes are averages, nobody can predict with certainty what will happen to individuals. Statistically, the best way to avoid breast cancer is to never get old. Failing that, lifestyle does make a difference. But aging is, and likely always will be, the main driver of cancer. Not exclusive, but main.

    3. Sawyer says:

      Short of exposing yourself to She Hulk levels of gamma rays, I don’t know of any lifestyles that could equal the negative effects of simply getting older. Is there any particular behavior you think has a greater correlation?

      1. David Gorski says:

        Oh, come on, you know it must be that “toxic” lifestyle and all those evil humors “toxins” causing breast cancer. :-)

  2. Windriven says:

    “I also recognize that part of the equation has to be an accurate understanding of the absolute numbers and what the individual woman being screened values.”

    Also what society values. Health care has costs. In the US it amounts to a bit under 18% of GDP and in much of the rest of the industrialized world 10-11%.

    The endpoint for all of us is death. We spend what we spend on health care for three reasons: to manage infectious diseases that would otherwise endanger the society, to forestall untimely death, and to improve quality of life during the the lifespan.

    It may seem cold to argue the benefits of mammography in dollars and cents but it is a necessary part of the analysis. There are many demands on GDP – food, shelter, investment, research, defense – and it is unlikely that we will spend appreciably more on health. Every dollar spent on an inefficient test or treatment is a dollar not spent on something more effective. Is the dollar spent on Mrs. M’s annual mammography as effective as a dollar spent on perinatal care for Mrs. P’s granddaughter?

    There are not enough dollars or enough health care workers for everyone to have unlimited healthcare. Do we organize this by means? The rich get as much as they can afford and the poor get whatever resources are left? By age? A lifetime ‘budget’ for health care expenses or a diminishing scale where more resources are invested in the young and productive? Perhaps we leave things as they are with a thousand interests pulling in a thousand different directions. It is grossly inefficient. But it saves us from thinking about awkward and unpleasant realities.

    The promise of science based medicine is to deliver efficiency in health care, to discard the useless and discover the useful. I wonder if we can ever have science based politico economics?

  3. Neal says:

    My wife is in her 40s. She was told to get a mammogram. The doctor said there’s no danger from the small amount of radiation, but didn’t mention the JAMA article, the Canadian study or the different alternative procedures that some sources seem to recommend (such as avoiding screenings before age 50, or screening based on need). We are frustrated and beg for help.

    1. How do we get informed consent when clinicians are so resistant to giving information, or resistant to study? Or how can we get our doctor to help us?
    2. What about radiation? The JAMA article did not address the risk from radiation or cumulative radiation from the procedure. There is evidence linking radiation to chronic illness and death. The JAMA article listed a handful of problems such as “overtreatment’. Isn’t death and disease caused by the diagnostic procedure at least worth considering?

    1. Uffish Thought says:

      A two view digital mammogram deposits ~3 mSv effective dose to the breast tissue.

      It’s estimated that a lifetime of annual mammograms would produce ~1.3-1.7 fatal breast cancers per 100,000 population.

      On average, in the US, we receive about 3 mSv of ionizing radiation from background sources such as cosmic radiation and earth sources (Radon gas from decaying radioactive sources). One’s personal dose increases if you live at high altitude (Denver), live where there is more ground radiation sources, with trans-continental and trans-oceanic air travel, from medical sources…

  4. Harriet Hall says:

    I am older than you and I vividly remember the arguments in medical journals when screening mammography was first introduced. Alarmists feared the radiation might cause more cancer deaths than the screening would prevent. Radiologists argued that their rays were quite safe. Medicine is far from an exact science; doctors do their best to apply the insufficient evidence that is available and to make decisions with inadequate information. Those who want certainty should go into politics or religion. (Or CAM).

    1. The Old Portland says:

      Dr. Hall,

      I take it you were responding to Neal’s post. He asked two reasonable questions that I, too, would like to see addressed.

      We all know that medicine is “far from an exact science,” but how do we know that our medical providers are “do[ing] their best to apply the insufficient evidence that is available” when they won’t discuss the most recent scientific findings with us?

      1. Harriet Hall says:

        I was actually responding to Dr. Gorski’s post itself. As for Neal’s questions, I don’t have the citations for the risks of radiation with mammography, but I know it has been very carefully considered by the experts and factored into the recommendations. The risk is low and has decreased with better technology. I am more concerned by the cumulative radiation from CT scans that are not always necessary.

        As for doctors who won’t discuss the evidence with patients, IMHO that is reason to look for a new doctor.

        1. Self Skeptic says:

          Dr. Hall, this seems self-contradictory. On the one hand, you’re saying you don’t know the literature, and are expressing your usual faith that the experts have taken everything into account, and should be trusted implicitly. On the other hand, you’re saying that a doctor who can’t or won’t discuss the actual evidence, should be fired.

          Which is it?

          1. Harriet Hall says:

            @self skeptic: Read more carefully. I didn’t say I didn’t know the literature. I said I don’t have the citations handy.

          2. Self Skeptic says:

            That’s fine; if you know the literature, I look forward to your discussion of it. (I don’t expect you to know it, off hand; that would be surprising. Being science-based, means being willing to go look at the primary literature carefully, before making judgments about what the experts have, and haven’t considered, and how well they’ve done so.

            What do you think should happen after a doctor tells a patient he/she doesn’t have the references handy, when the patient asks about the evidence? Should he/she offer to call the patient later to discuss it, or would it be okay for the doctor to say that he/she is sure that the experts have considered everything, so there is no need to discuss the evidence? The latter would save time and be easy, but it is an authoritarian approach, not a science-based one.

            1. weing says:

              “Being science-based, means being willing to go look at the primary literature carefully, before making judgments about what the experts have, and haven’t considered, and how well they’ve done so. ”
              That’s the stupidest definition I have ever heard. We would never get anywhere if we followed it. Why would you even bother having guidelines if you are going to be doing their jobs? Never mind whether you are even qualified to do their jobs.

            2. Harriet Hall says:

              Being science-based doesn’t mean you need to go back and look at the primary literature carefully each time you are asked about an issue. As Weing points out, there is no way a primary care provider could do that and still have time to see patients. There is a big difference between authoritarianism (relying on “authorities”) and relying on the considered opinions of a panel of experts who have examined all the primary literature in a field they know far better than you do. Experts are not “authorities” in the usual sense of authoritarianism, which is blind obedience to someone in power. Experts have no power except to advise.

              1. Self Skeptic says:

                Dr. Hall and Weing,

                I’m not sure how you can think that “experts have no power but to advise.” In medicine, the dominant experts codify the “standard of care” by issuing guidelines, in association with their specialty society. Doctors who do not practice according to these standards of care are opening themselves to being found guilty of malpractice in the case of a lawsuit, and of being disciplined or ostracized by their peers. Therefore, the dominating experts have great power, over all of us who seek medical care from mainstream medicine.

                Because of this, it is extremely important that the products of these experts (journal articles, other communications) and of their committees (guidelines, position statements, and political slogans like “Mammograms save lives”) be constantly scrutinized and critiqued by their peers in medicine and science. That is, it is important, if you think it is important that medicine be science-based, or at least keep moving in that direction.

                I don’t think you two understand yet, how the self-correction function of science works. There is no metaphysical force that corrects the experts when they get it wrong. Correction of errors depends on the voluntary assumption of responsibility, by everyone in the profession, to patrol their area of expertise, and call attention to biases and errors, as they arise, and as their consequences become manifest. The hierarchical organization of medicine doesn’t encourage this; but without it, science is dead in the water.

                Instead, you are recommending putting the dominant experts on a pedestal, and essentially setting up an unchallengeable priesthood. This is asking for trouble, of the kind commonly seen in any authoritarian system. Dr. Hall, you even suggested that looking at the available data and pointing out weak spots in guideline-writer’s recommendations, represents hubris. Try to put yourself in a scientist’s shoes, and think about how that argument looks. I’m sure you know enough about the theory of how science is done, to see that what might look like hubris in a military or medical hierarchy, is the daily, almost sworn duty, of every real scientist. If we’re not independently, critically examining the possible interpretations of our, and others’, data, and honestly communicating our findings, we’re not doing science.

                If you want to make a [i]policy[/i] argument, that everyone should pretend that the dominant team of medical experts belongs on a pedestal, because it creates (apparent) consensus among practitioners, and because this seeming consensus speeds up medical decision-making, and stimulates the faith of the public in medicine, go ahead and make that argument. Maybe without the hierarchy, chaos would ensue, and the net result would be worse than the current, authority-based system. I am open to arguments that sometimes science isn’t the most important thing, in medicine and public health. But let’s not pretend that policy and science are the same thing. We need to know when we are compromising science, for social reasons, or we’ll lose touch with physical reality.

                I would like to think that some reasonable accommodation can be made between what’s necessary for science to function within medicine (which includes constant critique of experts), and what is necessary for medicine to function in the community. One would think that a blog named Science-Based Medicine would be an appropriate place to discuss that.

              2. Harriet Hall says:

                “I’m not sure how you can think that “experts have no power but to advise.”

                Because that’s true. It is the medical boards and the courts that have the power to act against physicians who are not following the standard of care. And no body of experts alone can define the standard of care. It becomes standard only when the majority of clinicians in the community practice that way. In fact, there are cases where different groups of experts have issued different recommendations: scoliosis screening is a case in point. The USPSTF and the AAFP don’t recommend it; the AAOP and the AAP do.

                “I would like to think that some reasonable accommodation can be made between what’s necessary for science to function within medicine (which includes constant critique of experts), and what is necessary for medicine to function in the community.”

                I do think that. I don’t understand why you don’t.

              3. Harriet Hall says:

                “you are recommending putting the dominant experts on a pedestal, and essentially setting up an unchallengeable priesthood.”

                I am not. I never recommended, or even suggested, any such thing. You are mis-representing my nuanced stance in black-and-white cartoon pictures.

              4. Dave says:

                Also consider the sheer number of guidelines. There are several hundred cardiology guidelines. I saw an article a few years ago which tracked a patient in the ER for a relatively simple problem (I cant give the exact citation) and counted the number of guidelines which applied (including guidelines about the IV site etc) and there were nearly 70.

              5. Andrey Pavlov says:

                I’m sorry Self Skeptic, but you haven’t read all the relevant primary literature in medicine, you don’t hold a degree in the relevant science, and therefore you cannot be making a science based argument.

                But I forget sometimes you are The One who has read all the primary literature in all fields and therefore can make such proclamations.

                Perhaps I should go tell the cosmologists that they are doing things wrong. Because unless I do so science will be dead in the water. And I certainly don’t agree with their interpretation of the BICEP2 data and that is really darned important stuff.

                Or perhaps you should tell the ASME that their guidelines are wrong? Because you’ve read all the primary literature in engineering and understand the field well enough to do so?

                Or maybe, just maybe, we can recognize that we tend to have a much higher chance of looking like a pompous fool when criticizing the functioning and conclusions of a group of relevant experts in a field completely removed from our own (kind of like when Michio Kaku put his foot in his mouth by opening it to speak about evolution)?

                would like to think that some reasonable accommodation can be made between what’s necessary for science to function within medicine (which includes constant critique of experts), and what is necessary for medicine to function in the community.

                Funny that. So would we. Funnier still we have a better idea of what that would look like than someone who has no idea of the field which he is criticizing.

              6. Windriven says:

                “Instead, you are recommending putting the dominant experts on a pedestal, and essentially setting up an unchallengeable priesthood.”

                While the appeal to authority fallacy occasionally appears in these pages, I don’t think that was either weing’s or Hall’s point. Weing, by my reading, was noting that it is difficult to build a Mars lander if you first must go back to review the basis for believing that E=IR. And both, I think, were basing their arguments on the understanding that scientific consensus is always susceptible to new data. But that new data is likely to come from specialists and the attack on the old paradigm is also likely to come from specialists.

                How can any one individual realistically evaluate the ACC guidelines on statin use, the IPCC guidelines on global warming, public policy on NIH funding guidelines, AACR guidelines on screening mammography, safe exposure limits and TWAs for this chemical or that, and all the other consensus positions that might impact our lives directly or indirectly? It just isn’t doable.

                You can always ask your physician for evidence supporting diagnosis and treatment. Your internist recommends atorvastatin. You ask why. He explains the ACC guidelines. Do you seriously expect your internist to discuss the various studies that were used by ACC in developing those guidelines with you? Are you willing to pay for her time? Is your insurer?

                There is a difference between rational skepticism and, what?, cynicism? Cantankerousness?

                The experts could be wrong. No sh!t? Does that mean that my non-expert opinion is somehow better? Because mine can be wrong far more easily than theirs.

                You have to put your marker down somewhere. You can put it on fear, on superstition, on political directive, or you can put it on scientific consensus. That’s where I put mine.

              7. Dave says:

                Where does this “experts on a pedestal” idea come from? Guidelines are that – suggestions made by experts (ie people who have expert knowlege about the condition in question) to help practicing physicians make decisions about patient care, with every guideline having a disclaimer to look at the individual patient’s situation and tailor the guideline to fit. From a purely practical point of view, to use an example, if a patient comes in with chest pain due to an acute coronary syndrome I have to know which anticoagulants and medications are appropriate and the rationale thereof, which are found in guidelines for the care of, say, unstable angina. I don’t have to be able to quote the details of the studies which have led to those recommendations. I also have to know that if the same patient has his acute chest pain because s/he is anemic and hypotensive from a major gastrointestinal bleed, that the guidelines for anticoagulation, etc do not apply for that particular patient. I’m giving this as an example of how guidelines are used/not used in real life situations. I also realize (hope) that the guidelines will change for the better as newer meds or more info becomes available.

                I really dont understand the hatred SS has for guidelines or even how he thinks they are used. He seems to think we regard them as some religions regard the ten commandments – inviolable and etched in stone from God Himself. Not so.

              8. WilliamLawrenceUtridge says:

                Therefore, the dominating experts have great power, over all of us who seek medical care from mainstream medicine.

                Well, it’s a good thing that these “dominating experts” base their guidelines on a profound understanding of the medical literature – where it converges, and highlighting where it diverges.

                You make it sound like they simply pull the guidelines out of thin air, unicorn farts and rainbows, like there’s no discussion of the evidence and no acknowledging of the weaknesses, flaws and future directions in research. Consider perhaps, that you may merely not be familiar enough with the topic or the specific discussions to be aware of these debates.

                Dr. Hall, you even suggested that looking at the available data and pointing out weak spots in guideline-writer’s recommendations, represents hubris. Try to put yourself in a scientist’s shoes, and think about how that argument looks.

                Consider what your argument looks like to a scientist: you’ve dedicated your career to investigating issues of breast cancer screening and treatment. You contribute to the literature, pubilsh, criticize, attending meeting, and are recognized as a world-leading expert on the subject. Then someone you’ve never heard of, because they have no formal qualifications in or academic interactions with the breast cancer literature, accuses you of not understanding the data because your guidelines are not absolute and don’t cover every single variation in patient characteristics.

                Looks like Dunning-Kruger to me.

                Pretending the whole thing is based on hierarchy rather than evidence doesn’t make evidence appear, or disappear.

            3. WilliamLawrenceUtridge says:

              Being a skeptic should also mean that when discussing matters of scientific consequence, not mere rank quackery, one admits that experts who spend their days creating, evaluating and working with the scientific literature on the specific topic being discussed will always have a much, much more grasp and nuance of the literature. Dr. Hall is absolutely correct in deferring to these experts because even if she ceased all other activities bar becoming familiar with the primary literature she would still be less of an expert than someone who has done this, but also attends meetings, conducts research and corresponds with other scientists. One can’t become an expert in all areas of cancer, let alone all medicine. One can’t reasonably expect Dr. Hall to delve into the entire corpus of primary literature for every single post to determine the veracity of a series of statements by a panel of experts. That is unreasonable, unrealistic, and really comes across as more of an attempt to smear than an honest reflection of the situation.

              I mean do you really expect a doctor, particularly a general practitioner, to have, in their head, a full appreciation of all primary literature on all medical topics? If so, then why do we bother having medical specialities? We should just train everyone as these GPs with their apparently capacitous memories for all underlying scientific material.

              Science is authoritarian, and deferral to expert consensus guidelines is an appropriate response. To think otherwise is purest Dunning-Kruger.

              1. Self Skeptic says:

                You seem to think that because you don’t have any training or experience in science or medicine, and therefore have no option but to accept the word of the experts, everyone else shares your lack of ability. Now that’s Dunning-Kruger.

                No, I don’t expect a primary care doctor to know everything off the top of his or her head. That’s why I said, above, that it would be surprising, if Dr. Hall did know the literature, on the topic we’re discussing. See my comment to her and Weing, above, for a more nuanced discussion of the practical and cultural issues that stand in the way of making medicine truly science-based.

                I do expect that primary care providers won’t be able to check out personally, every guideline that they follow. But I would like to think that having to following these guidelines for practical reasons, would not prevent them from recognizing which of these guidelines is being disputed, nor from paying some attention to what the arguments are, and perhaps being able to convey the gist of the debate, to patients who want to be informed. That’s probably a small enough proportion of patients, that a doctor could take the time to get back to them, after surveying the state of the relevant field. But there is a snag, in that doctors aren’t trained to do that kind of survey. They are trained to obey the experts. And to save time, not spend it on seemingly idle discussion.

                Claiming a commitment to science-based medicine, yet simultaneously taking the stance that no one, including doctors and scientists, should presume to examine and critique the experts and data behind the current standard of care, is absurd, from a scientist’s viewpoint. I’m trying to get across that simple point.

                If you can’t get it, it doesn’t matter. But if the doctors here can’t get it, then science-based medicine in the literal sense does not have a bright future.

              2. Andrey Pavlov says:

                Claiming a commitment to science-based medicine, yet simultaneously taking the stance that no one, including doctors and scientists, should presume to examine and critique the experts and data behind the current standard of care, is absurd, from a scientist’s viewpoint. I’m trying to get across that simple point.

                And claiming to be smarter than everyone and simultaneously being a pompous asshat about it all whilst burning a straw man is hardly skeptical. Nobody here holds that position. We hold a much more nuanced one that recognizes the limitations of science as it pertains to medicine, medicine as it pertains to the practice of medicine, physicians as practicers of medicine, and expert panels as more authoritative than you or I on these topics.

                The fact is that you seem to not like the way in which the consensus is disputed in medicine nor the fact that we (unlike you) recognize our limitations in being able to adequately analyze the data. Well too bad on the first part – it is a different field and things are done differently; it would be asinine to think that the actual actions of scientific self correction would be the same in medicine as particle physics or any field to any other field. And the second part is a sign of your own hubris and pomposity. Science is also humble and scientists should also recognize when their individual view in a field outside their expertise (or to a level beyond their depth) is not as relevant as the experts.

              3. Windriven says:


                “no one, including doctors and scientists, should presume to examine and critique the experts and data behind the current standard of care, is absurd, ”

                Ooh, now that was a gargantuan straw man. I felt the crash when you knocked it over!

                No one has said that standard of care is immune from examination or criticism. But the criticism of string theory by a zoologist does not carry the same weight as criticism of the use of tamiflu for the treatment of influenza by, say, Mark Crislip.

              4. WilliamLawrenceUtridge says:

                You seem to think that because you don’t have any training or experience in science or medicine, and therefore have no option but to accept the word of the experts, everyone else shares your lack of ability.

                Nope. I think, based on my extensive reading of lay and even scientific works on the topic of medicine, that I know far, far less than these experts, and at this point in my life cannot and never will learn enough to contribute in a meaningful way to the conversation. Therefore, I accept the word of experts as far, far more informed than mine, and therefore far, far more likely to be correct.

                I do think that everyone else who is not such an expert shares my lack of ability – otherwise they would be experts. I don’t think it’s realistic for anyone but a full-time researcher on the topic to be able to contribute in a meaningful way to a scientific discussion on the topic – whatever it is. I think the idea that even an informed layperson can debate the details of a complex intervention and public health issue like mammography is folly.

                I do think it is the patient’s decision regarding what to do about mammography, given appropriate, honest information about the best-understood options available. Which is very far from saying “I think that patient can debate the details with their doctor in a meaningful way”.

                But there is a snag, in that doctors aren’t trained to do that kind of survey. They are trained to obey the experts.

                Good! Doctors should obey the guidelines, as best they can. Which doesn’t mean slavishly following them to the letter (unless you recognize that the letter of the guidelines includes statements about adapting them to the individual patient).

                Claiming a commitment to science-based medicine, yet simultaneously taking the stance that no one, including doctors and scientists, should presume to examine and critique the experts and data behind the current standard of care, is absurd, from a scientist’s viewpoint. I’m trying to get across that simple point.

                And my simple point is that to think you can do that in a meaningful way is folly. To think that anyone less than a full-time researcher can review the data, the opinions, the physiological underpinnings, the complexities of the research, the nuances of the individual publications, is folly. To think that you, in your spare time, can acquire the same degree of knowledge as the people who developed the guidelines, is rank arrogance that underestimates the complexity of the underlying literature and biology.

                Pretending that the experts somehow aren’t experts, somehow collectively missed something, to pretend their opinions do not reflect nuances in the data or the need to adapt to individual patients, to pretend that you know better, is also folly.

                I would be extremely intrigued to note any examples you have of a true outsider contributing something meaningful to a field in, say, the last 20 years, without having to become an insider in the process.

  5. Mika says:

    Speaking of change in medicine, I hear there’s a new analysis coming out from Cochrane and BMJ this week that challenges the use of Tamiflu (oseltamivir) and Relenza (zanamivir) in the treatment of influenza. Hopefully somebody at SBM will have the time to tackle that one when it’s out (somebody posted the apparently still embargoed press release in Facebook today).

  6. Michael Finfer, MD says:

    I am not sure that the vignette about Mrs. M is the best one to encourage a discussion on this topic. It says that her daughter died of breast cancer at age 37. That raises the possibility that there is a BRCA mutation in that family, and, in that case, I would have a hard time arguing against life-long screening mammograms for that patient.

  7. Allison H. says:

    Any place you’d recommend I go for information on mammogram recommendations in younger women? My mom was first diagnosed at 33 (and again at 36), and I recall reading somewhere that women with strong family histories get their first mammogram when they are ten years younger than their closest female relative was at her first diagnosis.

    I got one when I was 25. I had a lump in my lymph nodes, and my GP tried antibiotics to clear it up first. When it didn’t go away, he sent me to a…diagnostic center, I guess you’d call it? It was apparently policy that I get a mammogram as well as a sonogram, as I had just turned 25. Thankfully, it was nothing but fluid, and it went away within the week.

    I’m 28, in good shape, don’t drink, don’t smoke, no kids, no hormonal birth control, regular periods. I’ve thought about genetic testing (no one in my mother’s family had ever been diagnosed before her, but years later, one of her sisters was diagnosed in her early fifties). But in the meantime, is there anything that’s come out recently that supports or debunks the idea of getting one every year at such a young age?

    Thanks. Love your blog.

    1. Michael Finfer, MD says:


      Recommendations are very much dependent upon the situation. Whith your mother’s history, you might be elegible for genetic testing. What I suggest you do is see your doctor, and ask for a referral to a genetic counsellor. There is some work involved on your part. You will need to put together a family tree that is as complete as possible and that shows as many cases of any type of cancer as you can find out about.

      If there is a mutation in your family, I think the recommendations you would get would be different than the ones you would get if you risk was solely related to your mother’s history.

      If you are ready for this, I think that is the way to go. In order to get a good recommendation, I think you need more information.

      1. Allison H. says:

        Right, yeah. I just have never been able to shake reading that bit of advice, and I sometimes forget that my situation is comparatively rare, seeing as it’s all I know.

    2. Andrey Pavlov says:


      You can, I’m sure, understand that providing actual direct health advice to a specific person for a specific situation is well outside our ability here. Micheal makes about the only recommendation we could – and precisely what I would have written.

      There may be a genetic component. It is worth getting that tested. If that comes up negative that only means it isn’t a genetic component that we test for. It could be none or it could be one we don’t yet know to test for. Either way, the recommendations should be tailored carefully to your case and a genetic counselor is a good place to start and then be referred on from there. There are no blanket guidelines that exist to guide such a specific and outside-the-norm situation.

      Start with a good GP, referred to a genetic counselor, and go from there.

      Best wishes.

  8. Self Skeptic says:

    Dr. Gorski,
    Thanks for sharing your thoughts on these matters, in such detail. I appreciate it.

  9. rork says:

    I was adviser to my mom with a mammography-detected lump at age 75, and poured through the literature at the time (5 years ago), with a statistician’s eye. There wasn’t allot of data for women that old. All that to get to this:
    Gorski’s paragraphs about decision making for older women was as good a review as I have ever read. Outstanding service to the public. Consider repackaging some things for the more popular lay press – we can’t expect average “science journalist” to be that thorough.

  10. Self Skeptic says:

    Here’s some more, mostly intelligent, lay discussion of screening mammography, with comments. (Please excuse, if this has already been cited; it’s a week old, but I just ran across it while reading something else.)

  11. Roman Korol says:

    Uffish Thought: “A two view digital mammogram deposits ~3 mSv effective dose to the breast tissue”

    Here are two general references that may be helpful to the lurker and lay reader to put into context how relatively low is the dose that is absorbed by living tissue.

  12. Roman Korol says:

    Golly, I didn’t *ask* for that annoying pic! I don’t know where the system picks that up!

  13. Kate Anne Pritchard says:

    Dear David,

    This is a very helpful article. As a woman in her early fifties about to have her first mammogram my concern is the level of radiation to the breasts and the possibility of detection of tumours that would cause no harm if undetected.

    What advice do you have for women who are concerned about the potential harm that mammograms and the potential for inaccurate or false positive results?

    Kate Anne

  14. Molly says:

    As a mammo tech, I am shocked at some of the information spread about by insurance companies and physicians, so let me enlighten you with a few direct facts. First off, a mammo has relatively LOW radiation in comparison to other DI studies. The benefits to getting a mammo greatly outweigh any negatives. Your chance of getting breast cancer has practically ZERO to do with family history, unless it happened to be your mother or sister. Most people with breast cancer have NO family history. Age is just a number, more and more women under the age of 40 are getting breast cancer, I see it every day. In their case a u/s would be more beneficial as breast tissue is extremely dense, making a mammo hard to read. More and more obgyns are ordering u/s along with mammo as extra precaution. This is pointless unless a nodule is found, as you would be looking for a needle in a haystack. And finally, your risk of breast cancer increases with age, therefore these docs telling older women they no longer need to do mammos is a complete farce. Certain types of breast cancer are extremely aggressive, I’ve seen women diagnosed die within months. GET YOUR MAMMOS ONCE A YEAR LADIES. If you have any questions for me, I’ll give you a friend of mines number. She skipped hers only once and is currently dying of breast cancer.

    1. WilliamLawrenceUtridge says:

      Hi molly,

      Three things. First, do you know what an anecdote is? Second, do you know why they are unconvincing, scientifically? Third, how does your bold set of statements square with the scientific literature and Dr. Gorski’s discussion?

    2. Sawyer says:

      Age is just a number, more and more women under the age of 40 are getting breast cancer, I see it every day.

      And finally, your risk of breast cancer increases with age, therefore these docs telling older women they no longer need to do mammos is a complete farce.

      Molly, even if you completely disagree with the conclusions Dr. Gorski presented (this is admittedly still an unresolved issue), you really owe it to your patients to read up on basic statistics regarding age and breast cancer progression. In fact regardless of what the medical literature says, these two sentences you offered us are mutually exclusive. How did age not matter at the beginning of your post then suddenly matter halfway through?

      If these concepts have not been properly explained to you then your employer is not giving you adequate training. You may be a fantastic technician but this is a serious issue that needs to be corrected.

      A preemptive apology if that comes off judgmental.

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