Posts Tagged Mammography

The uncertainty surrounding mammography continues

Screening mammography

Mammography is a topic that, as a breast surgeon, I can’t get away from. It’s a tool that those of us who treat breast cancer patients have used for over 30 years to detect breast cancer earlier in asymptomatic women and thus decrease their risk of dying of breast cancer through early intervention. We have always known, however, that mammography is an imperfect tool. Oddly enough, its imperfections come from two different directions. On the one hand, in women with dense breasts its sensitivity can be maddeningly low, leading it to miss breast cancers camouflaged by the surrounding dense breast tissue. On the other hand, it can be “too good” in that it can diagnose cancers at a very early stage.

Early detection isn’t always better

While intuitively such early detection would seem to be an unalloyed Good Thing, it isn’t always. Although screening for early cancers appears to improve survival, the phenomenon of lead time bias can mean that detecting a disease early only appears to improve survival even if earlier treatment has no impact whatsoever on the progression of the disease. Teasing out a true improvement in treatment outcomes from lead time bias is not trivial. Part of the reason why early detection might not always lead to improvements in outcome is because of a phenomenon called overdiagnosis. Basically, overdiagnosis is the diagnosis of disease (in this case breast cancer but it is also an issue for other cancers) that would, if left untreated, never endanger the health or life of a patient, either because it never progresses or because it progresses so slowly that the patient will die of something else (old age, even) before the disease ever becomes symptomatic. Estimates of overdiagnosis due to mammography have been reported to be as high as one in five or even one in three. (Remember, the patients in these studies are not patients with a lump or other symptoms, but women whose cancer was detected only through mammography!) Part of the evidence for overdiagnosis includes a 16-fold increase in incidence since 1975 of a breast cancer precursor known as ductal carcinoma in situ, which is almost certainly not due to biology but to the introduction of mass screening programs in the 1980s.

As a result of studies published over the last few years, the efficacy of screening mammography in decreasing breast cancer mortality has been called into question. For instance, in 2012 a study in the New England Journal of Medicine (NEJM) by Archie Bleyer and H. Gilbert Welch found that, while there had been a doubling in the number of cases of early stage breast cancer in the 30 years since mass mammographic screening programs had been instituted, this increase wasn’t associated with a comparable decrease in diagnoses of late stage cancers, as one would expect if early detection was taking early stage cancers out of the “cancer pool” by preventing their progression. That’s not to say that Bleyer and Welch didn’t find that late stage cancer diagnoses decreased, only that they didn’t decrease nearly as much as the diagnosis of early stage cancers increased, and they estimated the rate of overdiagnosis to be 31%. These results are in marked contrast to the promotion of mammography sometimes used by advocacy groups. Last year, the 25 year followup for the Canadian National Breast Screening Study (CNBSS) was published. The CNBSS is a large, randomized clinical trial started in the 1980s to examine the effect of mammographic screening on mortality. The conclusion thus far? That screening with mammography is not associated with a decrease in mortality from breast cancer. Naturally, there was pushback by radiology groups, but their arguments were, in general, not convincing. In any case, mammographic screening resulted in decreases in breast cancer mortality in randomized studies, but those studies were done decades ago, and treatments have improved markedly since, leaving open the question of whether it was the mammographic screening or better adjuvant treatments that caused the decrease in mortality from breast cancer that we have observed over the last 20 years.

Given that it’s been a while since I’ve looked at the topic (other than a dissection of well-meaning but misguided mandatory breast density reporting laws a month ago), I thought now would be a good time to look at some newer evidence in light of the publication of a new study that’s producing familiar headlines, such as “Mammograms may not reduce breast cancer deaths“.

Here we go again.

Posted in: Cancer, Public Health

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Mandatory breast density reporting legislation: The law outpaces science, and not in a good way

Over the years, our bloggers here at Science-Based Medicine have written time and time again about the intersection of law and science in medicine. Sometimes, we support a particular bill or law, such as laws to protect children against religion-inspired medical neglect; laws making it harder for manufacturers of homeopathic “medicines” to deceive the public; or California Bill AB 2109, a bill whose intent was to make it more difficult for parents to obtain nonmedical exemptions to vaccine mandates but whose implementation after being passed into law was profoundly sabotaged by Governor Jerry Brown. or, more recently, California SB 277, a bill currently wending its way through the California legislature that would eliminate nonmedical exemptions to school vaccine mandates and has, not surprisingly, engendered extreme resistance from the antivaccine crowd, including by Robert F. Kennedy, Jr. In the vast majority of cases we explain how the law lets us down when it comes to science in medicine, and, unfortunately, examples are many: Naturopathic licensing laws; supplement regulation (or, more appropriately, lack of regulation); misguided, deceptive, and patient-hostile “right-to-try” laws; state laws regulating medical practice that allow quackery to flourish unchecked; laws regulating pharmaceutical cost transparency that ask the wrong question.

The case I will discuss here is unusual in that it is a case of the law getting ahead of what the science says in a manner that will likely do little, if any, good for patients, cause a lot of confusion until the science is worked out better, and end up costing patients money for little or no benefit. I am referring to laws mandating the reporting of high-breast-density to women with dense breasts undergoing mammography. These laws are sweeping the country (albeit not as rapidly as “right-to-try” laws), with a total of 22 states having passed them as of today since Connecticut became the first to do so in 2009. The most recent of these laws went into effect in my own state of Michigan exactly one week ago:

Women with dense breast tissue — the sort that can hide potentially deadly tumors from routine mammograms — must be notified in writing and encouraged to consider additional tests under a new state law that is effective Monday.

While mammograms remain the gold standard for detecting breast tumors, they’re less reliable in almost half of women with dense breast tissue. Dense or fibrous tissue shows up as splotches of white on a mammogram — so do tumors.

That will likely surprise many of the millions of women who rely on mammography for catching the earliest signs of cancer, said Nancy Cappello. The Connecticut woman was shocked in 2004, when her gynecologist found a lump — advanced cancer that had already spread to her lymph nodes — just months after a mammogram deemed her cancer-free.


Posted in: Cancer, Politics and Regulation, Public Health

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Screening for disease in people without symptoms: The reality

One of the most contentious questions that come up in science-based medicine that we discuss on this blog is the issue of screening asymptomatic individuals for disease. The most common conditions screened for that we, at least, have discussed on this blog are cancers (e.g., mammography for breast cancer, prostate-specific antigen screening for prostate cancer, ultrasound screening for thyroid cancer), but screening goes beyond just cancer. In cancer, screening is a particularly-contentious issue. For example, by simply questioning whether mammography saves as many lives lost to breast cancer as advocates claim, one can find oneself coming under fire from some very powerful advocates of screening who view any questioning of mammography as an attempt to deny “life-saving” screening to women. That’s why I was very interested when I saw a blog post on The Gupta Guide that pointed me to a new systematic review by John Ioannidis and colleagues examining the value of screening as a general phenomenon, entitled “Does screening for disease save lives in asymptomatic adults? Systematic review of meta-analyses and randomized trials.”

Before I get into the study, let’s first review some of the key concepts behind screening asymptomatic individuals for disease. (If you’re familiar with these concepts, you can skip to the next section.) The act of screening for disease is based on a concept that makes intuitive sense to most people, including physicians, but might not be correct for many diseases. That concept is that early intervention is more likely to successfully prevent complications and death than later intervention. This concept is particularly strong in cancer, for obvious reasons. Compare, for example, a stage I breast cancer (less than 2 cm in diameter, no involvement of the lymph nodes under the arm, known as axillary lymph nodes) with a stage III cancer (e.g., a tumor measuring greater than 5 cm and/or having lots of axillary lymph nodes involved). Five year survival is much higher for treated stage I than for treated stage III, and, depending on the molecular characteristics, the stage I cancer might not even require chemotherapy and can be treated with breast conserving surgery (“lumpectomy” or partial mastectomy) far more frequently than the stage III cancer. So it seems intuitively true that it would be better to catch a breast cancer when it’s stage I rather than when it’s stage III.

Posted in: Cancer, Clinical Trials, Epidemiology, Public Health

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In which Dr. Gorski is taken to task by an eminent radiologist for his posts on mammography


Introduction: An unexpected e-mail arrives

One of the consequences of the growing traffic and prominence of this blog over the last few years is that people who would otherwise have probably ignored what I or my partners in blogging write now sometimes actually take notice. Nearly a decade ago, long before I joined this blog as a founding blogger, if I wrote a post criticizing something that a prominent academic said, it was highly unlikely that that person would even become aware of it, much less bother to respond to whatever my criticism was. I was, quite simply, beneath their notice, sometimes happily, sometimes unhappily.

It appears that those days might be over. Last week Dr. Daniel Kopans, a prominent Harvard radiologist and well-known long-time defender of screening mammography, sent me a rather unhappy e-mail complaining about my “attack” on him on this blog, a charge that he repeated in a subsequent e-mail. Before I publish his initial e-mail verbatim (with his permission), I would like to point out that, while it’s true that I did criticize some of Dr. Kopans’ statements rather harshly in my post about the Canadian National Breast Screening Study (CNBSS), even characterizing one statement as a “howler,” I would hardly characterize what I wrote as an “attack.” That to me tends to imply a personal attack. Using Dr. Kopans’ apparent definition, what he has said and written about investigators like those running the CNBSS, as documented in my post, about H. Gilbert Welch, who published a large study in 2012 estimating the extent of overdiagnosis due to mammography, and the U.S. Preventive Services Task Force (USPSTF), the group that in 2009 suggested changing guidelines for routine screening mammography in asymptomatic women to begin at age 50 instead of age 40, would appear to also qualify as “attacks.”

Be that as it may, I also wondered why Dr. Kopans hadn’t noticed my CNBSS post until more than three months after it had originally appeared. Then, the day after I received Dr. Kopans’ e-mail, my Google Alert on mammography popped up an article in the Wall Street Journal by Dr. Kopans entitled “Mammograms Save Lives: Criticism of breast-cancer screenings is more about rationing than rationality.” That’s when I guessed that someone probably had either posted or e-mailed Dr. Kopans a link to my previous post in response to that article. Given the confluence of events, I think it’s a perfect time to discuss both Dr. Kopans’ e-mail and his article, because they cover many of the same issues. (more…)

Posted in: Cancer, Clinical Trials, Diagnostic tests & procedures, Public Health

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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.

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

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The Canadian National Breast Screening Study ignites a new round in the mammography wars

The last couple of weeks, I’ve made allusions to the “Bat Signal” (or, as I called it, the “Cancer Signal,” although that’s a horrible name and I need to think of a better one). Basically, when the Bat Cancer Signal goes up (hey, I like that one better, but do bats get cancer?), it means that a study or story has hit the press that demands my attention. It happened again just last week, when stories started hitting the press hot and heavy about a new study of mammography, stories with titles like Vast Study Casts Doubts on Value of Mammograms and Do Mammograms Save Lives? ‘Hardly,’ a New Study Finds, but I had a dilemma. The reason is that the stories about this new study hit the press largely last Tuesday and Wednesday, the study having apparently been released “in the wild” Monday night. People were e-mailing me and Tweeting at me the study and asking if I was going to blog it. Even Harriet Hall wanted to know if I was going to cover it. (And you know we all have a damned hard time denying such a request when Harriet makes it.) Even worse, the PR person at my cancer center was sending out frantic e-mails to breast cancer clinicians because the press had been calling her and wanted expert comment. Yikes!

What to do? What to do? My turn to blog here wasn’t for five more days, and, although I have in the past occasionally jumped my turn and posted on a day not my own, I hate to draw attention from one of our other fine bloggers unless it’s something really critical. Yet, in the blogosphere, stories like this have a short half-life. I could have written something up and posted it on my not-so-secret other blog (NSSOB, for you newbies), but I like to save studies like this to appear either first here or, at worst, concurrently with a crosspost at my NSSOB. (Guess what’s happening today?) So that’s what I ended up doing, and in a way I’m glad I did. The reason is that it gave me time to cogitate and wait for reactions. True, it’s at the risk of the study fading from the public consciousness, as it had already begun to do by Friday, but such is life.

Posted in: Cancer, Clinical Trials, Diagnostic tests & procedures, Public Health

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Once more into the screening breach: The New York Times did not kill your patient

One of the more depressing things about getting much more interested in the debate over how we should screen for common cancers, particularly breast and prostate cancer, is my increasing realization of just how little physicians themselves understand about the complexities involved in weighing the value of such tests. It’s become increasingly apparent to me that most physicians believe that early detection is always good and that it always saves lives, having little or no conception of lead time or length bias. Sadly, just last week, I saw another example of just this phenomenon in the form of an article written by Dr. George Lombardi entitled My Patient, Killed By The New York Times. The depth of Dr. Lombardi’s misunderstanding of screening tests permeates the entire article, which begins with his recounting a story about a patient of his, whose death he blames on The New York Times. After describing the funeral of this 73-year-old man who died of prostate cancer, Dr. Lombardi then makes an accusation:

This one filled me with a special discomfort as I knew a secret: He didn’t have to die. I knew it and he had known it. Had he told?

About 5 years ago he had just retired and had a lot more time on his hands. He was a careful man, lived alone, considered himself well informed. He got into the habit of clipping articles on medical issues and either mailing them to me or bringing them in. They came from a variety of sources and were on a variety of topics. He wasn’t trying to show me up. He was genuinely curious. I kidded him that maybe he’d like to go to medical school in his retirement. ‘No’ he laughed, ‘I just like to be in the know.’

When he came in for his physical in 2008 he told me he’d agree to the DRE but not the PSA (his medical sophistication extended to the use of acronyms: DRE stands for digital rectal exam where I feel the prostate with my gloved finger for any abnormality and PSA for prostatic [sic] specific antigen which is a blood protein unique to the prostate and often elevated in prostate cancer). He had read that the use of PSA as a screening test was controversial. This was the year that the United States Preventive Services Task Force, a government panel that issues screening guidelines, recommended against routine PSA screens for older men. It was often a false positive (the PSA was elevated but there was no cancer), led to unnecessary biopsies, and besides most prostate cancers at his age were indolent and didn’t need to be treated. I countered that prostate cancer was the second leading cause of cancer deaths in men and that it was better to know than not to know. This way it would be our decision. The patient with his doctor deciding what was best. But no, he wanted to stick to his guns and since the DRE was normal no PSA blood test was sent.

After describing a conversation with the man’s daughter, who said, “My father was killed by The New York Times,” Dr. Lombardi then goes on to anecdotal evidence and a cherry-picked publication to support his view, quoting an oncologist who says he’s “seeing more men presenting with advanced prostate cancer” and then referring to a single paper in the current Annals of Internal Medicine about PSA screening. Before I look at the article and a recently published paper on screening mammography that made the news, I can’t help but point out that I (mostly) agree with Dr. Lombardi when he says:

Public health doctors, policy experts and journalists tend to look at the population as a whole. It is a better story if it is one story. It makes a better headline. Their statistics are people I sit across from everyday trying to figure out what the future holds. We each have our job to do.

The problem is, of course, that Dr. Lombardi takes that observation and draws the wrong conclusion, namely that his patient died because of lack of screening. He attacks a straw man, sidestepping the true argument, namely that evidence shows that PSA screening probably causes more harm than good for men at average risk of prostate cancer. Unfortunately, Dr. Lombardi obviously does not understand some very basic concepts behind cancer screening, nor does he apparently recognize that doctors who deal with the population-level data that we have regarding screening tests and try to apply them to individual patients are actually looking in a very systematic way about what the benefits of screening are to the individual patient. More on that later. In the meantime, although I wouldn’t go quite as far as Dr. John Schumann did in criticizing Dr. Lombardi, I do view his lament as a jumping off point to look at some recent data on screening for the two most common cancers, breast and prostate.


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

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A holiday round in the mammography debate

There are times when the best-laid blogging plans of mice and men often go awry, and this isn’t always a bad thing. As the day on which so many Americans indulge in mass consumption of tryptophan-laden meat in order to give thanks approached, I had tentatively planned on doing an update on Stanislaw Burzynski, given that he appears to have slithered away from justice yet again. Then what to my wondering eyes should appear in my e-mail in box but news of a study that practically grabbed me by my collars, shook me, and demanded that I blog about it. As if to emphasize the point, suddenly e-mails started appearing by people who had seen stories about the study and, for reasons that I still can’t figure out after all these years, were interested on my take on the study. Yes, I realize that I’m a breast cancer surgeon and therefore considered an expert on the topic of the study, mammography. I also realize that I’ve written about it a few times before. Even so, it never ceases to amaze me, even after all these years, that anyone gives a rodential posterior about what I think. Then I started getting a couple of e-mails from people at work, and I knew that Burzynski had to wait or that he would be relegated to my not-so-secret other blog (I haven’t decided yet).

As is my usual habit, I’ll set the study up by citing how it’s being spun in the press. My local home town paper seems as good a place to begin as any, even though the story was reprinted from USA Today. The title of its coverage was Many women receiving unnecessary breast cancer treatment, study shows, with the article released the day before the study came out in the New England Journal of Medicine:

Posted in: Cancer, Diagnostic tests & procedures, Public Health

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The mammography wars heat up again (2012 edition)

One issue that keeps coming up time and time again for me is the issue of screening for cancer. Because I’m primarily a breast cancer surgeon in my clinical life, that means mammography, although many of the same issues come up time and time again in discussions of using prostate-specific antigen (PSA) screening for prostate cancer. Over time, my position regarding how to screen and when to screen has vacillated—er, um, evolved, yeah, that’s it—in response to new evidence, although the core, including my conclusion that women should definitely be screened beginning at age 50 and that it’s probably also a good idea to begin at age 40 but less frequently during that decade, has never changed. What does change is how strongly I feel about screening before 50.

My changes in emphasis and conclusions regarding screening mammography derive from my reading of the latest scientific and clinical evidence, but it’s more than just evidence that is in play here. Mammography, perhaps more than screening for any disease, is affected by more than just science. Policies regarding mammographic screening are also based on value judgments, politics, and awareness and advocacy campaigns going back decades. To some extent, this is true of many common diseases (i.e., that whether and how to screen for them are about more than just science), but in breast cancer arguably these issues are more intense. Add to that the seemingly eternal conflict between science and medicine communication, in which a simple message, repeated over and over, is required to get through, versus the messy science that tells us that the benefits of mammography are confounded by issues such as lead time and length bias that make it difficult indeed to tell if mammography—or any screening test for cancer, for that matter—saves lives and, if it does, how many. Part of the problem is that mammography tends to detect preferentially the very tumors that are less likely to be deadly, and it’s not surprising that periodically what I like to call the “mammography wars” heat up. This is not a new issue, but rather a controversy that flares up periodically. Usually this is a good thing.

And these wars just just heated up a little bit again late last week.

Posted in: Cancer, Diagnostic tests & procedures, Politics and Regulation, Public Health

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Dr. H. Gilbert Welch has written a new book Over-diagnosed: Making People Sick in the Pursuit of Health, with co-authors Lisa Schwartz and Steven Woloshin.  It identifies a serious problem, debunks medical misconceptions and contains words of wisdom.

We are healthier, but we are increasingly being told we are sick. We are labeled with diagnoses that may not mean anything to our health. People used to go to the doctor when they were sick, and diagnoses were based on symptoms. Today diagnoses are increasingly made on the basis of detected abnormalities in people who have no symptoms and might never have developed them. Overdiagnosis constitutes one of the biggest problems in modern medicine. Welch explains why and calls for a new paradigm to correct the problem. (more…)

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