Science-Based Medicine

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.

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I’ve been remiss in not mentioning this; so I’ll try to make up for it now. Recently, I did an interview on the Skeptikerpodden, a Swedish podcast. Unless you speak Swedish, you won’t understand much else of the podcast, but don’t worry. I don’t speak Swedish either, which is why my interview is in English. It starts at around the 44:00 mark.

Medicine is impossible. Really. The amount of information that flows out the interwebs is amazing and the time to absorb it is comparatively tiny.

If you work, sleep and have a family, once those responsibilities are complete there is remarkably little time to keep up with the primary literature. I have made two of my hobbies (blogging and podcasting) dovetail with my professional need to keep up to date, but most health care providers lack the DSM-4 diagnoses to consistently keep up.

So we all rely on short cuts. People rely on me to put new infectious disease information into context and there are those I rely upon to help me understand information both in my specialty and in fields that are unrelated to ID.

Up and down the medical hierarchies we trust that others are doing their best to understand the too numerous to count aspects of medicine that no single person could ever comprehend.

If I want to know about the state of the art on the treatment of atypical mycobacterium or how best to treat Waldenströms or who knows the most about diagnosing sarcoid, there is always someone who can distill their expertise on a topic to the benefit of the patient and my knowledge.

Trusting others is the biggest shortcut we routinely take in medicine to wade through the Brogdignagian amounts of information that flood into medical practice. We have to trust other clinicians, the researchers and the journals that all the information is gathered and interpreted honestly and accurately. Continue Reading »

In 2011, Americans spent some $30 billion on dietary supplements. Yet, except for the industry itself and a few politicians and “health freedom” advocates, you’d be hard pressed to find anyone (who’s given it some thought) of the opinion that dietary supplement regulation is adequate. Three recent reports, two from the government and one from a newspaper, demonstrate why this near-universal conclusion is warranted.

Another government report on lax supplement regulation

Here’s how an October, 2012, Department of Health and Human Services Office of Inspector General’s (OIG) report described the FDA’s regulatory authority:

DSHEA [Dietary Supplement Health and Education Act] does not require manufacturers to submit dietary supplements to FDA for safety or approval prior to sale. As a result, FDA has no comprehensive list of dietary supplements on the market. Dietary supplement manufacturers must ensure that their products are safe, they have evidence to substantiate structure/function claims, and that product labels are truthful and not misleading.

In other words, the fox guards the henhouse.

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In part I of this series I discussed clinical pathways – how clinicians approach problems and the role of diagnosis in this approach. In part II I discussed the thought processes involved in deciding which diagnostic tests are worth ordering.

In this post I will discuss some of the logical fallacies and heuristics that tend to bias and distort clinical reasoning. Many of these cognitive pitfalls apply to patients as well as clinicians.

Pattern Recognition and Data Mining

Science, including the particular manifestation we like to call science-based medicine, is about using objective methods to determine which patterns in the world are really real, vs. those that just seem to be real. The dire need for scientific methodology partly results from the fact that humans have an overwhelming tendency to automatically sift through large amounts of data looking for patterns, and we are very good at detecting patterns, even those that are just random fluctuations in that data.

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Daniel Amen loves SPECT scans (Single Photon Emission Computed Tomography). And well he should. They have brought him fame and fortune. They have rewarded him with a chain of Amen Clinics, a presence on PBS, lucrative speaking engagements, a $4.8 million mansion overlooking the Pacific Ocean, and a line of products including books, videos and diet supplements (“nutraceuticals”).  He grossed $20 million last year.   Amen is a psychiatrist who charges patients $3,500 to take pretty colored SPECT pictures of their brains as an aid to the diagnosis and treatment of conditions including brain trauma, attention-deficit hyperactivity disorder (ADHD), addictions, anxiety, depression, dementia, and obesity. He even does SPECT scans as a part of marriage counseling and for general brain health checkups.

SPECT imaging uses an injected radioisotope to measure blood flow in different areas of the brain. Amen is exposing patients to radiation and charging them big bucks because his personal experience has convinced him SPECT is useful. So far, he has failed to convince the rest of the scientific medical community.

Amen has just published an article in the journal Alternative Therapies entitled “It’s Time to Stop Flying Blind: How Not Looking at the Brain leads to Missed Diagnoses, Failed Treatments, and Dangerous Behaviors.”  It amounts to poorly-reasoned apologetics with false analogies, testimonials, and pretty pictures that don’t prove what he thinks they prove. Continue Reading »

There are many fallacies that undergird alternative medicine, which evolved into “complementary and alternative medicine” (CAM), and for which the preferred term among its advocates is now “integrative medicine,” meant to imply the “best of both worlds.” If I had to pick one fallacy that rules above all among proponents of CAM/IM, it would have to be either the naturalistic fallacy (i.e., that if it’s natural—whatever that means—it must be better) or the fallacy of antiquity (i.e., that if it’s really old, it must be better). Of course, the two fallacies are not unrelated. In the minds of CAM proponents, old is more likely to have been based on nature, and the naturalistic fallacy often correlates with the fallacy of antiquity. Basically, it’s a rejection of modernity, and from it flow the interest in herbalism, various religious practices rebranded as treatments (thousands of years ago, medicine was religion and religion was medicine—the two were more or less one and physicians were often priests as well), and the all-consuming fear of “toxins,” in which it is thought that the products of modernity are poisoning us.

Yes, there is a definite belief underlying much of CAM that technology and pharmaceuticals are automatically bad and that “natural” must be better. Flowing from that belief is the belief that people were happier and much healthier in the preindustrial, preagricultural past, that cardiovascular disease was rare or nonexistent, and that cancer was seldom heard of. Of course, it’s hard not to note that cancer and heart disease are primarily diseases of aging, and life expectancy was so much lower back in the day that a much smaller percentage of the population lived to advanced ages than is the case today. Even so, an implicit assumption among many CAM advocates is that cardiovascular disease is largely a disease of modern lifestyle and diet and that, if modern humans could somehow mimic preindustrial or, according to some, even preagricultural, lifestyles, that cardiovascular disease could be avoided. Not infrequently, evolutionary and genomic arguments are invoked, claiming that the estimated 10,000 years since the dawn of human agriculture is not a sufficiently long period of time for us to have evolved to handle diets rich in grains and meats and that we are “genetically wired” to exist on a diet like those of our paleolithic hunter-gatherer ancestors. For instance, in 2004, James H. O’Keefe Jr, MD and Loren Cordain, PhD wrote an article in the Mayo Proceedings entitled Cardiovascular Disease Resulting From a Diet and Lifestyle at Odds With Our Paleolithic Genome: How to Become a 21st-Century Hunter-Gatherer that asserted in essence, just that. Over the last decade, Cordain has become the most prominent promoter of the so-called “Paleo diet,” having written The Paleo Diet: Lose Weight and Get Healthy by Eating the Foods You Were Designed to Eat and multiple other books advocating a paleolithic-mimetic diet as the cure for what ails modern humans. Meanwhile, diets thought to reflect what our hunter-gatherer ancestors ate, such as the Paleo Diet consisting largely of animal and fish that can be hunted and fruits and vegetables that can be foraged for in the wild, have been promoted as a near-panacea for the chronic diseases of aging, such as cardiovascular disease and cancer.

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If science-based medicine reflects the application of the best evidence, then we should expect practices to change when new data emerges. In the long run that’s generally true, and the progressive gains we’ve seen in the management of disease reflect this. But in the short run, change can be maddeningly slow, and there are many areas of medicine where we could be doing a better job of applying what we already know to improve outcomes and reduce harms. One area where this is obvious is drug treatments, which can provide remarkable benefits but are also sources of significant harms.

Somewhat problematically, the real world is often the setting where the full extent of harms from treatments are identified. Bringing new drugs to market means tradeoffs: Do you demand larger and longer clinical trials to get as much information as possible about a drug before it’s sold? Or do you approve based on more preliminary, potentially weaker evidence, to meet (potentially) important patient need? There is no set formula or right answer to this questions – it’s ultimately a value judgement exercised by regulators like the FDA, who decide which drugs are allowed for sale (the benefits are assumed, overall, to exceed the harms) or removed for sale (when the opposite is felt to be the case).
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Film producer Eric Merola seems to think that there is a conspiracy of skeptics (whom he calls The Skeptics) who are fanatically hell-bent on harassing his hero, Brave Maverick Doctor Stanislaw Burzynski. According to his latest film Burzynski: Cancer Is A Serious Business, Part 2 (henceforth referred to as Burzynski II, to distinguish it from part 1, to which I will refer as Burzynski I), there is a shadowy cabal of Skeptics out there just waiting to swoop down on any Burzynski supporter who has the temerity to Tweet support for him, any cancer patient being treated by Burzynski who Tweets or blogs about it, and any cancer patient even thinking about going to the Burzynski Clinic. I know this because he’s made it very clear in the promotional materials of his movie that that’s what he thinks and that skeptics were going to be the main target of his “film making” in his latest hagiography devoted to Stanislaw Burzynski. Very clear indeed. And, given how ham-fisted he was in his conspiracy mongering in Burzynski I, I’d be lying if I didn’t admit that I was at least a little concerned, because Merola made an explicit promise to “name names.” So were some other skeptics. After all, Merola isn’t exactly known for intellectual honesty (or even talent) in film making. We expected a heavy duty sliming, and curiosity (not to mention concern over our reputations) made us very—shall we say?—curious about what Merola was going to say about us.

So it was with great interest that I learned that Burzynski II was going to be screened at a film festival in San Luis Obispo last weekend. Its DVD release having been delayed from March 5 to July 1, I had thought that my curiosity about the contents of the movie would probably have to wait, and it will, at least as far as seeing the movie. A review of the movie suggested dark insinuations about Burzynski critics abounded, but that was not enough. Fortunately, a small posse of skeptics, lead by the intrepid Brian Thompson, made posthaste for San Luis Obispo. When the reports and copious handwritten notes in perfect encoded reptilian script came back, however, I was faced with a problem. How does one review or discuss a movie second-hand? How does one report on a movie that one hasn’t seen, about which one has to trust the powers of observation (and not to mention the note taking capabilities) of someone else, no matter how well briefed beforehand about what to look for? I decided that there was only one thing to do, and that’s just to go ahead and do it. I realize that there are likely huge swaths of information missing, but I definitely got a flavor of the movie from Brian’s detailed account plus discussions, and a definite idea of how it is going to be promoted from what was reported to have been said during the Q&A. Then I’ll discuss each of these points, thus inflating the rather thin observations I have from our Skeptics into a real post. Unfortunately, more detail from me will have to wait until the official release of the movie, or until such a time as Merola tries to bring the movie to somewhere in my neck of the woods. (Wouldn’t that be amusing?)

So here are the five things I learned (secondhand) from the Burzynski II screening, thanks to The Skeptics.
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This is the second in a brief series of posts about how clinicians think. My purpose here is to elucidate how skeptical principles apply to clinical decision-making, but also as background to provide context to many of the articles we publish here.  In this installment I will review the factors that clinicians consider when deciding what tests to order for screening and when conducting a diagnostic workup.

The Gunshot Approach

Last week I discussed the “Dr. House” approach to medicine, using that particular TV character as an example of how medicine is often portrayed in fiction. Another aspect of the Dr. House image that is very misleading is his approach to diagnosis, which tends to be very linear. He decides what the most likely diagnosis is, then proceeds to either treat that entity or order a confirmatory diagnostic test. When that diagnosis fails, he then proceeds onto diagnosis B. A string of such failures then culminates in a flash of brilliance that allows him to make the actual obscure diagnosis and cure the patient. This approach is optimized for storytelling and drama, but is not how actual clinicians operate.

At the other end of the spectrum is what doctors often refer to as “the gunshot approach” – test for everything in hopes that you hit something. Another derogatory term that doctors throw around is “a fishing expedition,” referring to a diagnostic approach that amounts to hunting around for any possible diagnosis without having a real justification.

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