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Of SBM and EBM Redux. Part IV: More Cochrane and a little Bayes

NB: This is a partial posting; I was up all night ‘on-call’ and too tired to continue. I’ll post the rest of the essay later…

Review

This is the fourth and final part of a series-within-a-series* inspired by statistician Steve Simon. Professor Simon had challenged the view, held by several bloggers here at SBM, that Evidence-Based Medicine (EBM) has been mostly inadequate to the task of reaching definitive conclusions about highly implausible medical claims. In Part I, I reiterated a fundamental problem with EBM, reflected in its Levels of Evidence scheme, that although it correctly recognizes basic science and other pre-clinical evidence as insufficient bases for introducing novel treatments into practice, it fails to acknowledge that they are necessary bases. I explained the difference between “plausibility” and “knowing the mechanism.”

I showed, with several examples, that in the EBM lexicon the word “evidence” refers almost exclusively to the results of clinical trials: thus, when faced with equivocal or no clinical trials of some highly implausible claim, EBM practitioners typically declare that there is “not enough evidence” to either accept or reject the claim, and call for more trials—although in many cases there is abundant evidence, other than clinical trials, that conclusively refutes the claim. I rejected Prof. Simon’s assertion that we at SBM want to “give (EBM) a new label,” making the point that we only want it to live up to its current label by considering all the evidence. I doubted Prof. Simon’s contention that “people within EBM (are) working both formally and informally to replace the rigid hierarchy with something that places each research study in context.”

In Part II I responded to the widely held assertion, also held by Prof. Simon, that there is “societal value in testing (highly implausible) therapies that are in wide use.” I made it clear that I don’t oppose simple tests of basic claims, such as the Emily Rosa experiment, but I noted that EBM reviewers, including those employed by the Cochrane Collaboration, typically ignore such tests. I wrote that I oppose large efficacy trials and public funding of such trials. I argued that the popularity gambit has resulted in human subjects being exposed to dangerous and unethical trials, and I quoted language from ethics treatises specifically contradicting the assertion that popularity justifies such trials. Finally, I showed that the alleged popularity of most “CAM” methods—as irrelevant as it may be to the question of human studies ethics—has been greatly exaggerated.

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Posted in: Clinical Trials, Energy Medicine, Faith Healing & Spirituality, Medical Academia, Medical Ethics, Science and Medicine

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Of SBM and EBM Redux. Part III: Parapsychology is the Role Model for “CAM” Research

This is the third post in this series*; please see Part II for a review. Part II offered several arguments against the assertion that it is a good idea to perform efficacy trials of medical claims that have been refuted by basic science or by other, pre-trial evidence. This post will add to those arguments, continuing to identify the inadequacies of the tools of Evidence-Based Medicine (EBM) as applied to such claims.

Prof. Simon Replies

Prior to the posting of Part II, statistician Steve Simon, whose views had been the impetus for this series, posted another article on his blog, responding to Part I of this series. He agreed with some of what both Dr. Gorski and I had written:

The blog post by Dr. Atwood points out a critical distinction between “biologically implausible” and “no known mechanism of action” and I must concede this point. There are certain therapies in CAM that take the claim of biological plausibility to an extreme. It’s not as if those therapies are just implausible. It is that those therapies must posit a mechanism that “would necessarily violate scientific principles that rest on far more solid ground than any number of equivocal, bias-and-error-prone clinical trials could hope to overturn.” Examples of such therapies are homeopathy, energy medicine, chiropractic subluxations, craniosacral rhythms, and coffee enemas.

The Science Based Medicine site would argue that randomized trials for these therapies are never justified. And it bothers Dr. Atwood when a systematic review from the Cochrane Collaboration states that no conclusions can be drawn about homeopathy as a treatment for asthma because of a lack of evidence from well conducted clinical trials. There’s plenty of evidence from basic physics and chemistry that can allow you to draw strong conclusions about whether homeopathy is an effective treatment for asthma. So the Cochrane Collaboration is ignoring this evidence, and worse still, is implicitly (and sometimes explicitly) calling for more research in this area.

On the other hand:

There are a host of issues worth discussing here, but let me limit myself for now to one very basic issue. Is any research justified for a therapy like homeopathy when basic physics and chemistry will provide more than enough evidence by itself to suggest that such research is futile(?) Worse still, the randomized trial is subject to numerous biases that can lead to erroneous conclusions.

I disagree for a variety of reasons.

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Posted in: Acupuncture, Clinical Trials, Energy Medicine, Faith Healing & Spirituality, Herbs & Supplements, Homeopathy, Medical Academia, Medical Ethics, Science and Medicine

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Of SBM and EBM Redux. Part II: Is it a Good Idea to test Highly Implausible Health Claims?

Review

This is the second post in a series* prompted by an essay by statistician Stephen Simon, who argued that Evidence-Based Medicine (EBM) is not lacking in the ways that we at Science-Based Medicine have argued. David Gorski responded here, and Prof. Simon responded to Dr. Gorski here. Between that response and the comments following Dr. Gorski’s post it became clear to me that a new round of discussion would be worth the effort.

Part I of this series provided ample evidence for EBM’s “scientific blind spot”: the EBM Levels of Evidence scheme and EBM’s most conspicuous exponents consistently fail to consider all of the evidence relevant to efficacy claims, choosing instead to rely almost exclusively on randomized, controlled trials (RCTs). The several quoted Cochrane abstracts, regarding homeopathy and Laetrile, suggest that in the EBM lexicon, “evidence” and “RCTs” are almost synonymous. Yet basic science or preliminary clinical studies provide evidence sufficient to refute some health claims (e.g., homeopathy and Laetrile), particularly those emanating from the social movement known by the euphemism “CAM.”

It’s remarkable to consider just how unremarkable that last sentence ought to be. EBM’s founders understood the proper role of the rigorous clinical trial: to be the final arbiter of any claim that had already demonstrated promise by all other criteria—basic science, animal studies, legitimate case series, small controlled trials, “expert opinion,” whatever (but not inexpert opinion). EBM’s founders knew that such pieces of evidence, promising though they may be, are insufficient because they “routinely lead to false positive conclusions about efficacy.” They must have assumed, even if they felt no need to articulate it, that claims lacking such promise were not part of the discussion. Nevertheless, the obvious point was somehow lost in the subsequent formalization of EBM methods, and seems to have been entirely forgotten just when it ought to have resurfaced: during the conception of the Center for Evidence-Based Medicine’s Introduction to Evidence-Based Complementary Medicine.

Thus, in 2000, the American Heart Journal (AHJ) could publish an unchallenged editorial arguing that Na2EDTA chelation “therapy” could not be ruled out as efficacious for atherosclerotic cardiovascular disease because it hadn’t yet been subjected to any large RCTs—never mind that there had been several small ones, and abundant additional evidence from basic science, case studies, and legal documents, all demonstrating that the treatment is both useless and dangerous. The well-powered RCT had somehow been transformed, for practical purposes, from the final arbiter of efficacy to the only arbiter. If preliminary evidence was no longer to have practical consequences, why bother with it at all? This was surely an example of what Prof. Simon calls “Poorly Implemented Evidence Based Medicine,” but one that was also implemented by the very EBM experts who ought to have recognized the fallacy.

There will be more evidence for these assertions as we proceed, but the main thrust of Part II is to begin to respond to this statement from Prof. Simon: “There is some societal value in testing therapies that are in wide use, even though there is no scientifically valid reason to believe that those therapies work.”

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Posted in: Chiropractic, Clinical Trials, Energy Medicine, Health Fraud, History, Homeopathy, Medical Academia, Medical Ethics, Naturopathy, Politics and Regulation, Science and Medicine

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Vaccine Wars: the NCCAM Drops the Ball

If you go to the website of the National Center for Complementary and Alternative Medicine (NCCAM), you’ll find that one of its self-identified roles is to “provide information about CAM.” NCCAM Director Josephine Briggs is proud to assert that the website fulfills this expectation. As many readers will recall, three of your bloggers visited the NCCAM last April, after having received an invitation from Dr. Briggs. We differed from her in our opinion of the website: one of our suggestions was that the NCCAM could do a better job providing American citizens with useful and accurate information about “CAM.”

We cited, among several examples, the website offering little response to the dangerous problem of widespread misinformation about childhood immunizations. As Dr. Novella subsequently reported, it seemed that we’d scored a point on that one:

…Dr. Briggs did agree that anti-vaccine sentiments are common in the world of CAM and that the NCCAM can do more to combat this. Information countering anti-vaccine propaganda would be a welcome addition to the NCCAM site.

In anticipation of SBM’s Vaccine Awareness Week, I decided to find out whether such a welcome addition has come to fruition. The short answer: nope.

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Posted in: Chiropractic, Health Fraud, Homeopathy, Legal, Medical Ethics, Naturopathy, Politics and Regulation, Public Health, Science and the Media

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Uff Da! The Mayo Clinic Shills for Snake Oil

A couple of weeks ago, in a review of the Mayo Clinic Book of Home Remedies, Harriet Hall expressed relief that she hadn’t found any “questionable recommendations for complementary & alternative medicine (CAM) treatments” in that book:

Since “quackademic” medicine is infiltrating our best institutions and organizations, I wasn’t sure I could trust even the prestigious Mayo Clinic.

The Home Remedies book may be free of woo, but Dr. Hall was right to wonder if she could trust the Mayo Clinic. About a year ago I was asked to comment on an article in the American Journal of Hematology (AJH), in which investigators from the Mayo Clinic reported that among a cohort of lymphoma patients who were “CAM” users,

There was a general lack of knowledge about forms of CAM, and about potential risks associated with specific types of CAM…

This suggests the need to improve access to evidence-based information regarding CAM to all patients with lymphoma.

No surprise, that, but I couldn’t help calling attention to the paradox of one hand of the Mayo Clinic having issued that report even as the other was contributing to such ignorance:

The Mayo Clinic Book of Alternative Medicine details dozens of natural therapies that have worked safely for many patients in treating 20 top health issues. You may be surprised that Mayo Clinic now urges you and your doctor to consider yoga, garlic, acupuncture, dietary supplements and other natural therapies. Yet the record is clear. Many of these alternative therapies can help you achieve reduced arthritis pain, healthier coronary arteries, improved diabetes management, better memory function and more.

Mayo Clinic cover

Nor could such a paradox be explained by the right hand not having known what the left was doing: Brent Bauer, MD, the Director of the Mayo Clinic Complementary and Integrative Medicine Program, is both the medical editor of the Book of Alternative Medicine (MCBAM) and a co-author of the article in the AJH.

As chance would have it, I had picked up a copy of the latest (2011) edition of the MCBAM only a couple of days before Dr. Hall’s post. Does it live up to its promises? Do its “straight answers from the world’s leading medical experts” respond to “the need to improve access to evidence-based information regarding CAM?” Let’s find out. In some cases I’ll state the implied questions and provide the straight answers.

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Posted in: Acupuncture, Book & movie reviews, Chiropractic, Energy Medicine, Health Fraud, Homeopathy, Medical Academia, Medical Ethics, Naturopathy, Science and Medicine, Science and the Media

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The Guatemala syphilis experiment and medical ethics in science-based medicine

Several of the bloggers here at SBM have repeatedly criticized various clinical trials for so-called “complementary and alternative medicine” interventions for various conditions and diseases (or should I say dis-eases?) for being completely unethical. Examples include the misbegotten clinical trial for the Gonzalez protocol for pancreatic cancer, which — surprise, surprise! — ended up showing that patients undergoing Dr. Gonzalez’s combination of 150 supplements a day, dietary manipulations, and coffee enemas, actually did much worse than those undergoing standard of care, despite how depressingly poor the results of standard of care are; clinical trials of homeopathy in Honduras and other Third World countries, which both Wally Sampson and I lambasted; and ongoing clinical trial of chelation therapy for cardiovascular disease. I’ve also criticized the “autism biomed” movement, that amalgamation of parents who believe that vaccines cause autism and yet are willing to subject their children to all sorts of quackery to “cure” the “vaccine injury” of uncontrolled and unethical experimentation on autistic children. As valid as all these criticisms are, it is important to recognize that science-based medicine is not free of its own abuse of ethics.

A couple of weeks ago, I wrote about the concept of clinical equipoise. Clinical equipoise is a critical concept in any clinical trial. Basically, a state of clinical equipoise exists when there is genuine scientific uncertainty over which of the options being tested in/on living, breathing human beings is better, and any clinical trial in which a state of clinical equipoise does not exist is at the very least ethically dodgy and probably downright unethical. For example, when the occasional anti-vaccine activist argues for a randomized controlled clinical trial comparing vaccinated children and unvaccinated children, it’s easy to shoot that idea down as unethical because there is no clinical equipoise. The children receiving placebo vaccines would be put at a much higher risk of suffering harm compared to the vaccinated children because they would be left unprotected against life-threatening diseases. In the realm of conventional medicine, the reason that few cancer clinical trials involve a placebo control group anymore but instead test a new therapy either against the standard of care or with the standard of care is because in many, if not nearly all, cases placebo use in a cancer patient is unethical when there exists effective therapy, even if the therapy is not all that effective. What all this boils down to is that science is only part of the basis of science-based medicine. Medical ethics must take precedence. After all, arguably the most efficacious way to test a new antibiotic would be to infect people with the bacteria the antibiotic treats and then divide these people up into a placebo control group and a group receiving the antibiotics to see how each group does. After all, this is the sort of thing that the Nazis and Japanese did during World War II, and the same sort of dehumanization and abuse of research subjects that every ethical precept regarding human subjects research that has been developed since then, such as the Helsinki Declaration of 1964, has been designed to prevent.

Unfortunately, medical scientists in the U.S. have not always lived up to these precepts. The most famous example is arguably the Tuskegee syphilis experiment, in which poor black men with syphilis were studied and the control group denied effective therapy for syphilis even after it was known that penicillin was an effective treatment for syphilis. This study spanned 40 years, from 1932 to 1972, and is justifiably held up as one of the worst examples of research misconduct in American history, if not the history of the world. The shock the revelation of this study to the American public in 1972, when it learned of men dying of syphilis, women contracting syphilis, and babies being born with congenital syphilis, all unnecessarily, led to Belmont Report and the establishment of the Office for Human Research Protections (OHRP).

It turns out that there was an even worse atrocity against medical science perpetrated by U.S. investigators in Guatemala over 60 years ago that only now has come to light in stories in the New York Times, MSNBC, and elsewhere. So bad was the offense that Secretary of State Hillary Clinton and Secretary of Health and Human Services Kathleen Sebelius have issued a formal apology to the Guatemalan government for the experiments in which Guatemalan prisoners were intentionally infected with syphilis and then treated with antibiotics, an apology that President Obama reiterated in a personal telephone call to Guatemalan President Alvaro Colom on Friday.
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Posted in: Clinical Trials, Medical Ethics

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Chelation: Compounding Pharmacy’s Problems

Chelation is the provision of a substance to increase the body’s excretion of heavy metals. In poisoning situations (lead, aluminum, iron, etc.), chelation is medically necessary, objectively effective, and approved for use. But the same term has a completely different meaning in the alternative medicine universe, where proponents often believe heavy metal toxicity is the “one true cause” of disease, and chelation can undo microvascular inflammation, atherosclerosis, and even aging itself. From early days as an unproven treatment of coronary artery disease, its use has expanded to include autism, Alzheimer’s disease, cancer, and dozens of other diseases. Today, chelation is widely available. Regrettably, my own profession, pharmacy,  facilitates this pseudoscience by manufacturing and selling chelation products.

Provoked urine tests are a common entry point to chelation therapy. Patients are given a product to provoke heavy metal excretion. The urine is tested and the patient is informed that they’re “toxic” and require chelation. Unfortunately, these results are meaningless and provide no evidence that chelation is medically necessary. But that’s the justification used for advocating a treatment regimen that will be useless at best and fatal at worst. A recent Medical Letter review concluded:

Medical Letter consultants believe that the use of chelation therapy in non-standard protocols for unsubstantiated indications should be discouraged. The results of provoked urine testing are not an acceptable basis for such treatment.

Providing chelation to patients isn’t a straightforward matter. It’s typically an intravenous infusion (though there are some oral products). Unless you’re part of the dubious TACT trial, which has administration centres across the United States and Canada, there are few products commercially available. For example, edetate calcium disodium (EDTA) is approved for sale in the United States but not Canada. Edetate disodium (also called EDTA) is not approved for sale in either country. But these products are widely available: they’re manufactured by pharmacists in pharmacies.
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Posted in: Health Fraud, Medical Ethics, Pharmaceuticals

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Clinical equipoise versus scientific rigor in cancer clinical trials

A critical aspect of both evidence-based medicine (EBM) and science-based medicine (SBM) is the randomized clinical trial. Ideally, particularly for conditions with a large subjective component in symptomatology, the trial should be randomized, double-blind, and placebo-controlled. As Kimball Atwood pointed out just last week, in EBM, scientific prior probability tends to be discounted while in SBM it is not, particularly for therapies that are wildly improbable strictly on the basis of basic science, but for both the randomized clinical trial remains, in essence, where the “rubber hits the road,” so to speak. Indeed, when the prior probability of a therapy working based on preclinical basic science investigations appears high, EBM and SBM should be (and are, for the most part) more or less indistinguishable.

The ethics of clinical trials, however, demand a characteristic known as clinical equipoise. Stated briefly, for purposes of clinical trials, clinical equipoise demands that at the time a clinical trial is being carried out there be a state of genuine scientific uncertainty in the medical community over which of the drugs or treatments being tested is more efficacious and safer. One reason (among many) why the Gonzalez trial was completely unethical was a lack of clinical equipose. (Lack of adequate informed consent was another.) Lack of clinical equipoise is also the reason why a prospective randomized, double-blind, placebo-controlled clinical trial testing an unvaccinated group versus a vaccinated control group to determine whether vaccines cause autism would be completely unethical. Such a trial would egregiously violate the principle of clinical equipoise because the unvaccinated group would be left unprotected against potentially life-threatening vaccine-preventable diseases, and that is completely unacceptable from an ethical perspective. Consequently, we have had to rely on on the accumulation of data from less rigorous trial designs to demonstrate that there is no correlation between vaccines and autism. Even so, the accumulated weight of such evidence is enough, and for some questions that is the best we can do because scientific rigor sometimes conflicts with human subjects research ethics. This is an extreme example of lack of clinical equipoise, but it illustrates the point. If we know (or have good scientific reason to suspect) that one treatment is better than another, it is unethical to randomize patients to the arm that receives what is, based on what is known at the time of the trial, likely to be an inferior treatment.

Sometimes, however, the question of whether clinical equipoise exists in a clinical trial is not so obvious as it is for trials proposed by cranks. This situation sometimes crops up in clinical trials for cancer. I was reminded of this issue by a front page story in the New York Times yesterday, New Drugs Stir Debate on Basic Rules of Clinical Trials. In it, reporter Amy Harmon uses a classic human interest story to highlight the issue of clinical equipoise in a clinical trial for a new drug for melanoma that shows great promise. In brief, it is the story of two cousins, one of whom is receiving the new “wonder drug” (whether it is truly a wonder drug or not remains to be seen) in a clinical trial and one of whom is receiving the current standard of care for stage IV melanoma, which, to put it bluntly, sucks in that it has very little effect in prolonging life:
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Posted in: Cancer, Clinical Trials, Medical Ethics

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Evidence-Based Medicine, Human Studies Ethics, and the ‘Gonzalez Regimen’: a Disappointing Editorial in the Journal of Clinical Oncology Part 2

NB: If you haven’t yet read Part 1 of this blog, please do so now; Part 2 will not summarize it.

At the end of Part 1, I wrote:

We do not need formal statistics or a new, randomized trial with a larger sample size to justify dismissing the Gonzalez regimen.

In his editorial for the JCO, Mark Levine made a different argument:

Can it be concluded that [the] study proves that enzyme therapy is markedly inferior? On the basis of the study design, my answer is no. It is not possible to make a silk purse out of a sow’s ear.

That conclusion may be correct in the EBM sense, but it misses the crucial point of why the trial was (ostensibly) done: to determine, once and for all, whether there was anything to the near-miraculous claims that proponents had made for a highly implausible “detoxification” regimen for cancer of the pancreas. Gonzalez himself had admitted at the trial’s inception that nothing short of an outcome matching the hype would do:

DR. GONZALEZ: It’s set up as a survival study. We’re looking at survival.

SPEAKER: Do you have an idea of what you’re looking for?

DR. GONZALEZ: Well, Jeff [Jeffrey White, the director of the Office of Cancer Complementary and Alternative Medicine at the NCI—KA] and I were just talking a couple weeks ago. You know, to get any kind of data that would be beyond criticism is—-always be criticism, but at least three times.

You would want in the successful group to be three times — the median to be three times out from the lesser successful groups.

So, for example, if the average survival with chemo, which we suspect will be 5 months, you would want my therapy to be at least — the median survival to be at least 15, 16, 17 months, as it was in the pilot study.

We’re looking for a median survival three times out from the chemo group to be significant.

Recall that the median survival in the Gonzalez arm eventually turned out to be 4.3 months.

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Posted in: Cancer, Clinical Trials, Health Fraud, Medical Academia, Medical Ethics, Politics and Regulation, Science and Medicine

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Evidence-Based Medicine, Human Studies Ethics, and the ‘Gonzalez Regimen’: a Disappointing Editorial in the Journal of Clinical Oncology Part 1

Background: the distinction between EBM and SBM

An important theme on the Science-Based Medicine blog, and the very reason for its name, has been its emphasis on examining all the evidence—not merely the results of clinical trials—for various claims, particularly for those that are implausible. We’ve discussed the distinction between Science-Based Medicine (SBM) and the more limited Evidence-Based Medicine (EBM) several times, for example here (I began my own discussion here and added a bit of formality here, here, and here). Let me summarize by quoting John Ioannidis:

…the probability that a research finding is indeed true depends on the prior probability of it being true (before doing the study), the statistical power of the study, and the level of statistical significance.

EBM, in a nutshell, ignores prior probability† (unless there is no other available evidence) and falls for the “p-value fallacy”; SBM does not. Please don’t bicker about this if you haven’t read the links above and some of their own references, particularly the EBM Levels of Evidence scheme and two articles by Steven Goodman (here and here). Also, note that it is not necessary to agree with Ioannidis that “most published research findings are false” to agree with his assertion, quoted above, about what determines the probability that a research finding is true.

The distinction between SBM and EBM has important implications for medical practice ethics, research ethics, human subject protections, allocation of scarce resources, epistemology in health care, public perceptions of medical knowledge and of the health professions, and more. EBM, as practiced in the 20 years of its formal existence, is poorly equipped to evaluate implausible claims because it fails to acknowledge that even if scientific plausibility is not sufficient to establish the validity of a new treatment, it is necessary for doing so.

Thus, in their recent foray into applying the tools of EBM to implausible health claims, government and academic investigators have made at least two, serious mistakes: first, they have subjected unwary subjects to dangerous but unnecessary trials in a quest for “evidence,” failing to realize that definitive evidence already exists; second, they have been largely incapable of pronouncing ineffective methods ineffective. At best, even after conducting predictably disconfirming trials of vanishingly unlikely claims, they have declared such methods merely “unproven,” almost always urging “further research.” That may be the proper EBM response, but it is a far cry from the reality. As I opined a couple of years ago, the founders of the EBM movement apparently “never saw ‘CAM’ coming.”

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Posted in: Cancer, Clinical Trials, Medical Academia, Medical Ethics, Politics and Regulation, Science and Medicine

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