The US Preventive Services Task Force (USPSTF) recommends that everyone aged 50-75 be screened for colon cancer with any one of three options: colonoscopy every 10 years, flexible sigmoidoscopy every 5 years, or fecal occult blood testing (FOBT) every year. Conventional colonoscopy is considered the “gold standard” since it allows for direct detection and biopsy of early cancers and removal of precancerous polyps. It involves passing a long colonoscope via the rectum through the full length of the colon and is also known as optical or visual colonoscopy. A newer and less invasive alternative, virtual colonoscopy or CT colonography, is being promoted by some as the test of choice. Others disagree. One area of controversy is that CTs frequently find “incidentalomas” that require further investigation. An article in the journal Radiology highlights this problem, describing “the clinical drama that follows screening or diagnostic tests.” (more…)
Archive for Diagnostic tests & procedures
Everything you know may be wrong. Well, not really, but reading the research of John Ioannidis does make you wonder. His work, concentrated on research about research, is a popular topic here at SBM. And that’s because he’s focused on improving the way evidence is brought to bear on decision-making. His most famous papers get to the core of questioning how we know what we know (or what we assume) to be evidence. (more…)
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…)
Occasionally, there are topics that our readers want — nay, demand — that I cover. This next topic, it turns out, is one of them. It’s a link to a TED Talk. I’m guessing that most of our readers have either viewed (or at least heard of) TED talks. Typically, they are 20-minute talks, with few or no slides, by various experts and thought leaders. Many of them are quite good, although as the TED phenomenon has grown I’ve noticed that, not unexpectedly, the quality of TED Talks has become much more uneven than it once was. Be that as it may, beginning shortly after it was posted, readers of both this blog and my other super-not-so-secret other blog started peppering me with links to a recent TED Talk by Dr. Deborah Rhodes at the Mayo Clinic entitled A tool that finds 3x more breast tumors, and why it’s not available to you.
At first, I resisted.
After all, I’ve written about the issues of screening mammography, the USPSTF guideline changes (here, too), the early detection of cancer (including lead time and length time bias, as well as the Will Rogers effect), and a variety of other topics related to the early detection of breast cancer, such as overdiagnosis and overtreatment. Moreover, to put it bluntly, there really isn’t anything radically new in Dr. Rhodes’ talk, at least not to anyone who’s been in the field of breast cancer for a while. Certainly, there’s no new conceptual breakthrough in breast imaging and screening described. As I will discuss in more depth later in this post, there’s an interesting application of newer, smaller, and more sensitive detectors with a much better spatial resolution. It’s cool technology applied to an old problem in breast cancer, but something radical, new, or ground-breaking? Not so much. What Dr. Rhodes describes in her talk is the sort of device that, when I read about it in a medical journal, produces a reaction along the lines of, “Nice technology. Not ready for prime time. I hope it works out for them, though. Could be good.” So it was with molecular breast imaging (MBI), which is the topic of Dr. Rhodes’ talk. So I continued to resist for about two or three weeks.
Then our very own Harriet Hall sent me the link. I cannot resist Harriet. When she suggests that perhaps I should blog about a topic, it’s rare that my response would be anything other than, “Yes, ma’am. How soon would you like that post and how many words?” I keed, of course, but only just. The best I could come up with was a wishy-washy “But this isn’t really anything all that new,” which is true enough, but the way Dr. Rhodes tried to sell the audience on the idea of her technology brings up a lot of issues important to our audience. I also thought it was important to put this technology in perspective. So here I go. First, I’ll start by describing what really set my teeth on edge about Dr. Rhodes’ talk. Then I’ll go to the primary literature (namely her brand, spankin’ new article in Radiology describing the technology) and discuss the technique itself.
Oprah’s buddy Dr. Christiane Northrup and breast thermography: The opportunistic promotion of quackery
As many readers know, October is Breast Cancer Awareness Month. What that generally means at our cancer center and in the rest of the “real world” is that, during the month of October, extra effort is made to try to raise awareness of breast cancer, to raise money for research, and promote screening for cancer. Unfortunately, what Breast Cancer Awareness Month means around the Science-Based Medicine blog is that a lot of breast cancer-related pseudoscience and outright quackery will be coming at us fast and furious. There’s no way, of course, that I can deal with it all, but there’s one area of medical pseudoscience related to breast cancer that I just realized that none of us has written about on SBM yet. Actually, it’s not really pseudoscience. At least, the specific technology isn’t. What is pseudoscience is the way it’s applied to breast cancer and in particular the way so many “alternative” medicine and “complementary and alternative medicine” (CAM) practitioners market this technology to women. The technology is breast thermography, and the claim is that it’s far better than mammography for the early detection of breast cancer, that it detects cancer far earlier.
I’ve actually been meaning to write about thermography, the dubious claims made for it with regard to breast cancer, and the even more dubious ways that it’s marketed to women. In retrospect, I can’t believe that I haven’t done so yet. The impetus that finally prodded me to get off my posterior and take this on came from what at the time was an unexpected place but in retrospect shouldn’t have been. You’ve met her before quite recently when SBM partner in crime Peter Lipson took her apart for parroting anti-vaccine views and even citing as one of her sources anti-vaccine activist Sherri Tenpenny. I’m referring, unfortunately, to one of Oprah Winfrey’s stable of dubious doctors, Dr. Christiane Northrup. Sadly, Peter’s example of her promotion of vaccine pseudoscience is not the first time we at SBM have caught Dr. Northrup espousing anti-vaccine views. We’ve also harshly criticized her for her promotion of “bioidentical hormones” and various dubious thyroid treatments. However, Dr. Northrup is perhaps most (in)famous for her advocating on Oprah’s show the use of Qi Gong to direct qi to the vagina, there apparently to cure all manner of female ills and promote fantastic orgasms in the process. This little incident ought to tell you nearly all that you need to know about her. Even Oprah looked rather embarrassed in the video in which Dr. Northrup led her audience in directing all that qi goodness “down below.”
What brought Dr. Northrup to my attention again was my having joined her e-mail list. As you might imagine, I’m on a lot of e-mail lists, ranging from that of Mike Adams, to Generation Rescue, to Joe Mercola and beyond. I do it all for you, in order to have the blogging material come to me rather than my having to seek it out. True, the price is that my e-mail in box is frequently clogged with quackery, but it’s a small price to pay. This time around, Dr. Northrup’s e-mail brought my attention to a post of hers, Best Breast Test: The Promise of Thermography. It was truly painful to read, and I consider it inexcusable that someone who claims to be an advocate of “women’s health” could write something that reveals such ignorance. But, then, I suppose I shouldn’t be surprised after her recent flirtation with anti-vaccine views. If it isn’t already complete, Dr. Northrup’s journey to the Dark Side is damned close to complete. You’ll see what I mean right from her very introduction:
PRELUDE: THE PROBLEM WITH SCREENING
If there’s one aspect of science-based medicine (SBM) that makes it hard, particularly for practitioners, it’s SBM’s continual requirement that we adjust what we do based on new information from science and clinical trials. It’s not easy for patients, either. To lay people, SBM’s greatest strength, its continual improvement and evolution as new evidence becomes available, can appear to be inconsistency, and that seeming inconsistency is all too often an opening for quackery. Even when there isn’t an opening for quackery, it can cause a lot of confusion; some physicians are often resistant to changing their practice. It’s not for nothing that there’s an old joke in medical circles that no outdated medical practice completely dies until a new generation of physicians comes up through the ranks and the older physicians who believe in the practice either retire or die. There’s some truth in that. As I’ve said before, SBM is messy. In particular, the process of applying new science as the data become available to a problem that’s already as complicated as screening asymptomatic people for a disease in order to intervene earlier and, hopefully, save lives can be fraught with confusion and difficulties.
Certainly one of the most contentious issues in medicine over the last few years has been the issue of screening for various cancers. The main cancers that we most commonly subject populations to routine mass screening for include prostate, colon, cervical, and breast cancer. Because I’m a breast cancer surgeon, I most frequently have to deal with breast cancer screening, which means, in essence, screening with mammography. The reason is that mammography is inexpensive, well-tested, and, in general, very effective.
Or so we thought. Last week, yet another piece of evidence to muddle the picture was published in the New England Journal of Medicine (NEJM) and hit the news media in outlets such as the New York Times (Mammograms’ Value in Cancer Fight at Issue).
A topic of growing interest (and concern) at SBM is laboratory and diagnostic test pseudoscience. Bogus tests are everywhere, and Kimball Atwood recently discussed several of them. But over the past several years, diagnostic tests have emerged that appear to be science-based and offer gene-level insights into your health. And these tests don’t even require a physician’s visit – just a swab of saliva and a credit card get you reams of information on your genetics, traits, and risks of dozens of diseases. It looks like the ultimate in consumer health information, with the potential to offer truly personalized treatment strategies. Companies like 23andme, deCODEme, and Navigenics all promise “genetic insights” to improve your health. How could this information be anything but helpful?
Personalized medicine describes medical practices that use information about a person’s genes, proteins, and environment to prevent, diagnose and treat disease. Science-based practice has routinely incorporated environmental advice (e.g., diet and exercise) into medical management. And there are a number of genetic tests in routine use that are well established, clinical validated, and are highly predictive of future outcomes, such as tests for Huntington’s disease and hereditary breast cancer.
You can’t help but have noticed that many of the links in this post are to articles on Quackwatch. That’s because the site is chock full of useful information about bogus tests, far more than can be found elsewhere. There you will find a more comprehensive list of bogus tests than I’ve mentioned here, and a larger list of laboratories peddling them. You’ll also find an article on “Dubious Genetic Testing” co-authored by the Quackwatch founder, Stephen Barrett, and our own Harriet Hall, and an article about bogus “biomedical treatments” for autism showing that—surprise!—Doctor’s Data and Genova Diagnostics are major players there, too.
I stand by all of those statements. It turns out that Doctor’s Data is not pleased that Dr. Barrett has so thoroughly blown the company’s cover.
I don’t want knowledge. I want certainty!
If there’s a trait among humans that seems universal, it appears to be an unquenchable thirst for certainty. It is likely to be a major force that drives people into the arms of religion, even radical religions that have clearly irrational views, such as the idea that flying planes into large buildings and killing thousands of people is a one-way ticket to heaven. However, this craving for certainty isn’t expressed only by religiosity. As anyone who accepts science as the basis of medical therapy knows, there’s a lot of the same psychology going on in medicine as well. This should come as no surprise to those committed to science-based medicine because there is a profound conflict between our human desire for certainty and the uncertainty that is always inherent in so much of our medical knowledge. The reason is that the conclusions of science are always provisional, and those of science-based medicine arguably even more so than many other branches of science.
In fact, one of the hardest things for many people to accept about science-based medicine is that the conclusions of science are always subject to change based on new evidence, sometimes so much so that even those of us “in the biz” can become a bit disconcerted at the rate at which knowledge we had thought to be secure changes. For example, think of how duodenal peptic ulcer disease was treated 25 years ago and then think about how it is treated now. Between 1984 and 1994, a revolution occurred on the basis of the discovery of H. pylori as the cause of most of the gastric and peptic ulcer disease we see. Where in 1985 we treated PUD with H2-blockers and other drugs designed to block gastric acid secretion, now antibiotics represent the mainstay of treatment and are curative at a much higher success rate than any treatment other than surgery and without the complications of surgery. I’m sure any other physician here could come up with multiple other examples. In my own field of breast cancer surgery, I look back at how we treated breast cancer 22 years ago, when I first started residency, and how we treat it now, and I marvel at the changes. If such changes can be disconcerting even to physicians dedicated to science-based medicine, imagine how much more disconcerting they are to lay people, particularly when they hear news reports of one study that produces one result, followed just months later by a report of a different study that gives a completely different result.