Articles

Archive for Surgical Procedures

Early detection of cancer, part 2: Breast cancer and MRI

Note: If you haven’t already, you should read PART 1 of this two-part series. It defines several terms that I will be using in this post, and I don’t plan on explaining them again, given that they were explained in detail in Part 1. Of course, if you’re a medical professional and already know what lead time bias, length bias, and stage migration are, then it goes without saying that you should still read Part 1 for its scintillating prose.

ResearchBlogging.orgWhen last I left this topic three weeks ago, I had discussed why detecting cancer at ever-earlier stages and ever-smaller sizes is not necessarily an unalloyed good. At that time, I discussed in detail a landmark commentary in the New England Journal of Medicine entitled, Advances in Diagnostic Imaging and Overestimations of Disease Prevalence and the Benefits of Therapy. The article, although nearly 15 years old, rings just as true today in its cautioning doctors about whether ever-increasing diagnostic sensitivity that imaging technology and new blood tests were (and are) providing was actually helping patients as much as we thought it was. Before we dive into this problem as applied to breast cancer, let’s review what Drs. Black and Welch had to say about screening tests for breast cancer 15 years ago, as way of background and linking my last post and this one:

Before the widespread use of mammography, most breast cancers were discovered on physical examination, as palpable lumps. In one of the few studies to assess directly the accuracy of physical examination in screening for breast cancer, only 27 percent of tumors more than 1.0 cm in diameter and 10 percent of those less than 1.0 cm in diameter were detected by physical examination. However, the mean size of breast cancers detected by state-of-the-art screening mammography is about 1.0 cm, and many of the cancers detected as microcalcifications are only a few millimeters in size.

Again, prevalence depends on the degree of scrutiny. According to the Connecticut Tumor Registry, clinically apparent breast cancer afflicts about 1 percent of all women between the ages of 40 and 50 years. In a recent medicolegal autopsy study, however, small foci of breast cancer were found in 39 percent of women in this age group. Most cancers were in the form of ductal carcinoma in situ. Furthermore, over 45 percent of the women with cancer had two or more lesions, and over 40 percent had bilateral lesions. Although it has been argued that such small in situ lesions are not detected by and are therefore irrelevant to screening mammography, about half the lesions in that study were detected, usually as microcalcifications, on postmortem plain-film radiography of the resected breasts. Because of continual technical improvements and increasingly broad criteria for the interpretation of mammograms, the detection threshold for breast cancer has fallen considerably since the time of the Breast Cancer Screening Project of the Health Insurance Plan of Greater New York (1963 to 1975). This can explain the increased prevalence of cancer on mammographic screening, from 2.717 to 7.614 per 1000 examinations (with the incidence increasing from 1.517 to 3.214 per 1000 examinations). The lower detection threshold can also explain the increase in the percentage of carcinomas in situ (stage 0) among all mammographically detected cancers — from 12.7 percent to over 30 percent. The principal indication for biopsy has changed from suspicious mass to suspicious microcalcifications. This can explain why the reported incidence of breast cancer has increased and why most of the increase is in smaller lesions, particularly ductal carcinoma in situ.

About a year ago, three major articles hit the medical press that made me start thinking about this more than I had in the past. It’s my job, after all, because breast cancer surgery is a large part of my practice, and I do breast cancer lab-based research. What also tweaked me not to put off doing part 2 of this series is that, just two days ago, there was an abstract presented at the American Society of Clinical Oncology Meeting (where I still am today) that also serves to highlight just how difficult this question of integrating a test as sensitive as MRI into a screening regimen for and preoperative evaluation of breast cancer is and how MRI should fit into in this regimen can be.
(more…)

Posted in: Clinical Trials, Public Health, Science and Medicine, Science and the Media, Surgical Procedures

Leave a Comment (4) →

Barriers to practicing science-based surgery

ResearchBlogging.orgMuch to the relief of regular readers, I will now change topics from those of the last two weeks. Although fun and amusing (except to those who fall for them), continuing with such material for too long risks sending this blog too far in a direction that no one would want. So, instead, this week it’s time to get serious again.

A few weeks ago, I wrote about factors that lead to the premature adoption of surgical technologies and procedures or the “bandwagon” or “fad” effect among surgeons. By “premature,” I am referring to widespread adoption “in the trenches,” so to speak, of a procedure before good quality evidence from science and clinical trials show it to be superior in some way to previously used procedures, either in terms of efficacy, cost, time to recover, or other measurable parameters. As I pointed out before, laparoscopic cholecystectomy definitely fell into that category. The popularity of the procedure spread like wildfire in the early 1990s before there was any good quality data supporting its superiority to the “old-fashioned” gold standard procedure of open cholecystectomy. Another example, although not nearly as dramatic because the number of patients for whom the procedure would be appropriate is much smaller, is transanal endoscopic microsurgery. However, the difficulties in practicing science- and evidence-based medicine don’t just include fads and bandwagon effects. The example of laparoscopic cholecystectomy notwithstanding (which was largely driven by marketing and patient demand), surgical culture is deeply conservative in that it can be very reluctant to change practice even there is very strong evidence saying that they should.
(more…)

Posted in: Basic Science, Cancer, Surgical Procedures

Leave a Comment (2) →

Colon “cleanses”: A load of you know what…

Death begins in the colon.

Perhaps you’ve heard this little bit of “alternative medicine” wisdom. Oddly enough, I had never heard it until well after I had become a surgeon (although my first thought upon hearing it was that it would make a killer name for a rock band or a blog). That’s when I began encountering claims that seemed to indicate that constipation was the most evil thing in the world, something that must be avoided at all costs. Naturally, I wondered just what the heck was meant by this bit of “wisdom.” What, I wondered, was it based on? What, I wondered, was the purpose of it? To answer this question, recently I decided to go back and review what people say about colon health:

Have you ever considered this simple question: Are you clean inside?

(more…)

Posted in: Science and Medicine, Surgical Procedures

Leave a Comment (39) →

When the popularity of new surgical procedures outpaces science

ResearchBlogging.orgIn science- and evidence-based medicine, the evaluation of surgical procedures represents a unique challenge that is truly qualitatively different from the challenges in medical specialties. Perhaps the most daunting of these challenges is that it is often either ethically unacceptable or logistically impossible to do the gold-standard clinical trial, a double-blind, randomized placebo trial for an operation. After all, the “placebo” in a surgical trial involves patients to anaesthesia, making an incision or incisions like the ones used for the operation under study, and then not doing the operation. Clearly, even leaving the ethics aside, it’s impossible to blind the surgeons and operative team involved to which treatment, real surgery or placebo, the patient is receiving without having a different surgeon do the surgery from the one overseeing the postoperative care of the patient, with the operative surgeon barred from communicating to the postoperative surgeon what happened in the operating room and from participating in the postoperative care of the patient upon whom he operated. This sort of restriction, besides being also highly dubious ethically speaking, goes against the grain of surgical culture, in which a surgeon is expected to provide the postoperative care for his patients almost as a matter of surgical honor. A final problem that complicates any surgical trial is that surgeons of differing technical operating skill will necessarily be involved, and surgical skill is indeed very important in determining outcome. Although there have been examples of double-blinded trials with sham surgery as placebo, for example, in injecting dopamine-producing cells into the brain to treat Parkinson’s disease, difficulties doing such studies tend to force us as surgeons in many cases either to rely on retrospective data, prospective non-randomized data, or, when we’re lucky, a prospective randomized (but not double-blinded) trial of one surgical procedure versus another.
(more…)

Posted in: Clinical Trials, Medical Ethics, Science and Medicine, Surgical Procedures

Leave a Comment (13) →

Hype over science: Does acupuncture really improve the chances of success for in vitro fertilization?

There it was on Friday greeting me on the ABC News website: “Study: Acupuncture May Boost Pregnancy” in bold blue letters, with the title of the webpage being “Needles Help You Become Pregnant.” The story began:

It sounds far-fetched sticking needles in women to help them become pregnant but a scientific review suggests that acupuncture might improve the odds of conceiving if done right before or after embryos are placed in the womb.

The surprising finding is far from proven, and there are only theories for how and why acupuncture might work. However, some fertility specialists say they are hopeful that this relatively inexpensive and simple treatment might ultimately prove to be a useful add-on to traditional methods.

By the end of the day, the story was all over the media, including radio, TV, news websites, the blogosphere, and various other outlets, all trumpeting the message that a scientific study says that acupuncture can help infertile couples conceive. Nary a skeptical word seemed to be found. Knowing very well just how far parents will go to conceive, I was curious: Did this study actually say what the media says it said? What was so new and radical about this study that it rated a press release and a lot of promotion? Do we here at SBM (particularly Steve) need to rethink our extreme skepticism about acupuncture, given the poor quality evidence and lack of even a glimmer of a convincing physiologic mechanism to explain its supposed activities?
(more…)

Posted in: Acupuncture, Clinical Trials, Energy Medicine, Science and Medicine, Surgical Procedures

Leave a Comment (8) →

Dr. Judah Folkman (1933-2008): The epitome of what a science-based physician should be

The name of this blog is Science-Based Medicine. The reason it is so called is because we, the bloggers who will be contributing, believe that “the best method for determining which interventions and health products are safe and effective is, without question, good science.” Sadly, one of the people who best represented this very sort of philosophy, Dr. Judah Folkman (1933-2008), has died. Dr. Folkman was the epitome of everything that a science-based surgeon or physician should be, and he was first among my scientific and surgical heroes.
(more…)

Posted in: Basic Science, Medical Academia, Pharmaceuticals, Surgical Procedures

Leave a Comment (4) →

On the nature of “alternative” medicine cancer cure testimonials

No doubt you’ve come across them before, either on the Internet, printed advertisements, or radio and TV ads: Alternative medicine cancer “testimonials.” They are the primary means by which “alternative” therapies for cancer (or just about any other disease) are promoted and the primary “evidence” that is used to “prove” the efficacy of non-evidence-based therapies. There’s no doubt that they sure can sound convincing. Typically, what you will see or hear is a chipper-looking and -sounding person who claims that this treatment “cured” his or her cancer. These testimonials almost always include many or all of these elements: First, the cancer patient receives the diagnosis, after which she is lost and suffering at the hands of “conventional” doctors, who either cannot or do not wish to understand and who cannot do anything for her. Often, this will take the form of the classic alt-med cliche that the patient was “sent home to die.” Then, when all hope seems lost, the patient discovers an alternative medicine “healer” or treatment. It is not infrequently described in quasireligious terms, like a revelation or something that brings the patient out of the darkness and into the light. Naturally, there is resistance from the patient’s doctors, family, and/or friends, who warn against it, with doctors warning of dire consequences if the patient abandons conventional medicine. But the patient, convinced by dubious practitioners, friends, and, of course, previous testimonials, “sees” that the treatment “works” in a way that medical science cannot and survives. Infused with fervor, the patient now wants to spread the word. Often, the patient is now selling the remedy. Perhaps you’ve seen such testimonials or heard them on the radio and thought: “Gee, this sounds great. I wonder if it works.”

The answer is: Almost certainly not.
(more…)

Posted in: Cancer, Health Fraud, Science and the Media, Surgical Procedures

Leave a Comment (24) →
Page 4 of 4 1234