Screen detection and tumor growth rates. Cancers have different growth rates, which determine their potential to be detected by screening. Tumor A remains microscopic and undetectable by current technology (although more sensitive tests in the future might render it detectable). Tumor B eventually becomes detectable by screening (*), but its growth rate is so slow that it will not cause symptoms during the life of the individual; its detection will result in overdiagnosis. Tumor C is capable of metastasizing, but it grows slowly enough that it can be detected by screening (*); for some, this early detection will result in survival. Tumor D grows very quickly and therefore is usually not detected by screening. This will present as an interval cancer (i.e. detected clinically in the interval between screening examinations) and has a particularly poor prognosis. Note that of the four tumor types, only Tumor C has the potential to benefit from screening. Red dashed lines represent the natural history of a tumor in the absence of detection by screening. (Figure 1 from Gates, 2014).
A new stool DNA test was recently approved by the FDA for colon cancer screening. My first reaction was “Yay! I hope it’s good enough to replace all those unpleasant, expensive screening colonoscopies.” But of course, things are never that simple. I wanted to explain the new test for our readers; but before I could start writing, some other issues in cancer screening barged in and demanded to be included. They exemplify the dilemmas we face with every screening test. We have covered these issues before, but mainly in reference to mammography and prostate (PSA) screening. My article morphed into a CLT sandwich: colon, lung, and thyroid cancer screening.
The current issue of American Family Physician has a great article on cancer screening. It uses lucid graphics to illustrate lead time bias, length time bias, and overdiagnosis bias, as well the effect of varying tumor growth rates on screening success rates, all concepts that have been covered by Dr. Gorski here. Briefly, screening may do more harm than good if:
- It detects cancerous cells that never would have developed into invasive cancers or harmed the patient in any way;
- Early diagnosis and treatment decrease quality of life without reducing death rates; or
- The test falsely indicates cancer in patients who don’t have it or fails to indicate cancer in some who do. (more…)
Who would you guess authored a 250-page report which begins with this Preface?
This report marks the culmination of an intensive four-year review of quackery and its impact on the elderly. . . As this report details, quackery has traveled far from the day of the pitchman and covered wagon to emerge as big business. Those who orchestrate and profit from the sale and promotion of these useless and often harmful “health” products are no longer quaint and comical figures. They are well organized, sophisticated and persistent. [We estimate] the cost of quackery – the promotion and sale of useless remedies promising relief from chronic and critical health conditions – exceeds $10 billion a year. The costs of quackery in human terms, measured in disillusion, pain, relief forsaken or postponed because of reliance on unproven methods, is more difficult to measure, but nonetheless real. All too frequently, the purchaser has paid with his life. While the impact of quackery on our lives has been increasing and growing in sophistication, public and private efforts designed to address and control this problem have diminished, been redirected or disbanded.
Naturopathy has been legal in Connecticut for almost 90 years, but with a scope of practice limited to counseling and a few treatments like physiotherapy, colonic hydrotherapy and “natural substances.” There was no specific authority to diagnose and treat. All of that changed on October 1, 2014, courtesy of the Connecticut legislature, which, in the words of the American Association of Naturopathic Physicians (AANP), “modernized” the naturopathic scope of practice.
Actually, the legislature did nothing of the sort. Naturopathy is based on the prescientific concept of vitalism, and we find it right there in the very first paragraph of the new law. Naturopathy is defined as:
diagnosis, prevention and treatment of disease and health optimization by stimulation and support of the body’s natural healing processes, as approved by the State Board of Natureopathic [sic] Examiners, with the consent of the Commissioner of Public Health. . .
Also included in the expanded scope of practice are:
ordering diagnostic tests and other diagnostic procedures, . . . ordering medical devices, including continuous glucose monitors, glucose meters, glucose test strips, barrier contraceptives and durable medical equipment; and . . . removing ear wax, removing foreign bodies from the ear, nose and skin, shaving corns and calluses, spirometry, tuberculosis testing, vaccine administration, venipuncture for blood testing and minor wound repair, including suturing.
Ladies, how would you like a chiropractor to deliver your baby? How about perform your annual well-woman exams, such as breast exam, bi-manual pelvic exam, speculum exam, recto-vaginal exam and Pap smear?
Sound out of their league? I thought so too. Way out. But, in some parts of the U.S., the law allows chiropractors to do all of these things and a great deal more. Including “adjusting” your basset hound.
A 2011 survey asked chiropractic regulatory officials whether their jurisdictions (all states, plus D.C., Virgin Islands and Puerto Rico, but I’ll refer to them collectively as the “states”) allowed 97 different diagnostic, evaluation, and management procedures. The results were recently reported and interpreted in the Journal of Manipulative and Physiological Therapeutics, in an article authored by Mabel Chang, DC, MPH, who was primarily responsible for the survey. Missouri allows the most procedures (92) and Texas, the fewest (30). A handful of states did not respond or did not respond to all questions, but the overall response rate was 96%. Results from a survey of Canada, Australia and New Zealand will be reported in a separate article. (more…)
It’s that time of year when every day I can expect to see at least one patient with a concern about Lyme disease. In Lyme-endemic regions such as Western Massachusetts, where I practice pediatrics, summer brings a steady stream of children to my office with either the classic Lyme rash (erythema chronicum migrans, or ECM), an embedded tick, a history of a tick bite, or non-specific signs or symptoms that may or may not be due to Lyme disease. Sometimes the diagnosis is relatively straightforward. A child is brought in after a parent has pulled off an engorged deer tick, and there is a classic, enlarging ECM rash at the site of the bite. More often the presentation is less clear, requiring detective work and science-based reasoning to make an informed decision and a diagnostic and therapeutic plan based on the best available evidence. Depending on the story, the plan may include immediate treatment without any testing (as in the straightforward case described above), immediate testing without treatment pending test results, or waiting as we watch and see how a rash progresses before doing anything. An example of this latter course of action would be when a patient comes in with a pink swelling at the site of a new tick bite. In this case, it may not be clear if the swelling is a Lyme rash or simply a local reaction to the bite, a much more common occurrence. The classic ECM rash (an enlarging, red, circular, bull’s-eye rash at or near a tick bite) typically develops 1-2 weeks after a tick bite, but can occur anywhere from 3-30 days later. It then expands and darkens over another 1-3 weeks before fading. This classic rash is not the most common rash of Lyme disease, however, as it occurs in only about 30% of cases. Instead, the rash may be uniformly pink or red (or even darker in the center) without the target-like appearance, or may be a linear rash, expanding outward from the tick bite site. In the case of a patient who comes in with a vague, pink swelling within a day few days of a tick bite, we will typically wait and see what happens to the rash. If it is a local reaction, it will likely resolve within another few days. With Lyme disease, the rash will continue to enlarge and declare itself as an ECM rash. Another unclear and not uncommon situation is when a patient comes in with non-specific symptoms such as fatigue, musculoskeletal pains, and headache. If warranted by the history and the physical exam, we may in this case order Lyme testing. This may not give us an answer even if the patient has Lyme disease, because results are often negative in the first few weeks of the disease. In this case, if symptoms persist or evolve, we will repeat the testing in another few weeks at which point true Lyme disease will test positive and can then be treated. The good news is that the treatment of Lyme disease, particularly in the early, localized phase of the disease, is extremely safe and effective with a 14-day course of antibiotics. The testing is also relatively straightforward, with very good sensitivity and specificity when performed correctly. And this is where the bad news comes… (more…)
Last week I wrote about doctors who order unnecessary tests, and the excuses they give. Then I ran across an example that positively flabbered my gaster. A friend’s 21-year-old son went to a board-certified family physician for a routine physical. This young man is healthy, has no complaints, has no past history of any significant health problems and no family history of any disease. The patient just asked for a routine physical and did not request any tests; the doctor ordered labwork without saying what tests he was ordering, and the patient assumed that it was a routine part of the physical exam. The patient’s insurance paid only $13.09 and informed him that he was responsible for the remaining $3,682.98 (no, that’s not a typo). I have a copy of the Explanation of Benefits: the list of charges ranged from $7.54 to $392 but did not specify which charges were for which test. It listed some of the tests as experimental and not covered at all by the insurance policy, and one test was rejected because there was no prior authorization. (more…)
While cleaning out some old files, I was delighted to find an article I had clipped and saved 35 years ago: a “Sounding Boards” article from the January 25, 1979 issue of The New England Journal of Medicine. It was written by Joseph E. Hardison, MD, from the Emory University School of Medicine; it addresses the reasons doctors order unnecessary tests, and its title is “To Be Complete.” Today we have many more tests that can be ordered inappropriately and the article is even more pertinent and deserves to be re-cycled. He says,
When challenged and asked to defend their reasons for ordering or performing unnecessary tests and procedures, the reasons given usually fall under one of the following excuses…
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…)
One size rarely fits all. Most medical knowledge is derived from studying groups of subjects, subjects who may be different in some way from the individual who walks into the doctor’s office. Basing medicine only on randomized controlled studies can lead to over-simplified “cookbook” medicine. A good clinician interprets study results and puts them into context, considering the whole patient and using clinical judgment to apply current scientific knowledge appropriately to the individual.
CAM practitioners claim to be providing individualized treatments. Homeopaths look up symptoms like “dreams of robbers,” “sensation of coldness in the heart,” and “chills between 9 and 11 AM” in their books, and naturopaths quiz patients in great depth about their habits and preferences; but they don’t have a plausible rationale for interpreting the information they gather. And they have not been able to demonstrate better patient outcomes from using that information.
A new concept, “precision medicine,” was recently featured in UW Medicine, the alumni magazine of my alma mater, the University of Washington School of Medicine. Precision medicine strives to provide truly individualized care based on good science. It identifies the individual variations in people that make a difference in our ability to diagnose and treat accurately. Peter Byers, MD, director of the new Center for Precision Diagnostics at the University of Washington, calls it “the coolest part of medicine.” (more…)
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.