I’ve written more times than I can remember about the phenomenon of overdiagnosis and the phenomenon that is linked at the hip with it, overtreatment. Overdiagnosis is a problem that arises when large populations of asymptomatic, apparently healthy people are screened for a disease or a condition, the idea being that catching the disease at an earlier stage in its progression will allow for more successful treatment. Two prominent examples include—of course—screening for breast cancer with mammography and screening for prostate cancer with prostate-specific antigen (PSA) testing, and I’ve written about the problem of overdiagnosis with each of them on many occasions. Basically, overdiagnosis occurs when the screening test picks up what we call “preclinical” disease (i.e., disease that hasn’t become symptomatic) that, if left untreated, would never become symptomatic or endanger the health or life of the patient). Although intuitively, it seems to the lay public (and, truth be told, most doctors) that detecting cancer earlier must be inherently better, it turns out that it’s way more complicated than you think. There is a price to be paid for early diagnosis in the form of overtreatment of disease that doesn’t need treatment and for disease that is destined to threaten the life of the patient earlier treatment doesn’t always result in better outcomes. Also, whenever you screen for a condition in asymptomatic people, you will always—always—find much more of it, and the significance of those added diagnoses is not always clear, as a new study in JAMA Oncology shows.
DCIS and mammography: Some background
Before I get to the meat of the study, from my perspective, nowhere is the problem of overdiagnosis and overtreatment in cancer screening as pronounced than in the condition known as ductal carcinoma in situ (DCIS). DCIS is commonly referred to as “stage 0” breast cancer and is characterized by milk duct cells that appear malignant but remain confined to the milk ducts. In other words, they haven’t invaded the tissue surrounding the ducts. In general, DCIS is treated similarly to breast cancer, with surgical excision, either by mastectomy or breast-conserving surgery, followed by radiation therapy if breast conserving surgery is used. Then, depending on its hormone receptor status, adjuvant treatment consists of blocking estrogen for five years. The rationale for this treatment is the view of DCIS as being a precursor to fully invasive breast cancer and that treating the DCIS will prevent the development of breast cancer. Over the last couple of decades, however, it has become clear that not all DCIS is created equal. Much of it will never progress to breast cancer in the lifetime of the woman (particularly if the woman is older, which means less time for fully malignant transformation to occur). Evidence suggesting this includes studies showing an increase in DCIS incidence by 16-fold since the 1970s, when mammography started to be introduced on a large scale, with little change in the incidence of invasive cancer. Today, 20-25% of mammography-detected breast cancer diagnoses are DCIS; forty years ago, DCIS was an uncommon diagnosis, except associated with an invasive cancer.
One of the difficult things about science-based medicine is determining what is and isn’t quackery. While it is quite obvious that modalities such as homeopathy, acupuncture, reflexology, craniosacral therapy, Hulda Clark’s “zapper,” the Gerson therapy and Gonzalez protocol for cancer, and reiki (not to mention every other “energy healing” therapy) are the rankest quackery, there are lots of treatments that are harder to classify. Much of the time, these treatments that seemingly fall into a “gray area” are treatments that have shown promise in animals but have never been tested rigorously in humans or are based on scientific principles that sound reasonable but, again, have never been tested rigorously in humans. (Are you sensing a pattern here yet?) Often these therapies are promoted by true believers whose enthusiasm greatly outstrips the evidence base for their preferred treatment. Lately, I’ve been seeing just such a therapy being promoted around the usual social media sources, such as Facebook, Twitter, and the like. I’ve been meaning to write about it for a bit, but, as is so often the case with my Dug the Dog nature—squirrel!—other topics caught my attention.
I’m referring to a diet called the ketogenic diet, and an article that’s been making the rounds since last week entitled “Ketogenic diet beats chemo for almost all cancers, says Dr. Thomas Seyfried.” Of course, when I see a claim such as that, my first reaction is, “Show me the evidence.” My second reaction is, “Who is this guy?” Well, Dr. Seyfried is a professor of biology at Boston College, who’s pretty well published. He’s also working in a field that has gained new respectability over the last five to ten years, namely cancer metabolism, mainly thanks to a rediscovery of what Otto Warburg discovered over 80 years ago. What Warburg discovered was that many tumors rely on glycolysis for their energy even in environments with adequate oxygen for oxidative phosphorylation, which generates the bulk of the chemical energy used by cells. I described this phenomenon in more detail in a post I did four years ago about a drug that looks as though its anticancer properties come from its ability to reverse the Warburg effect. (more…)
Last week, I wrote a magnum opus of a movie review of a movie about a physician and “researcher” named Stanislaw Burzynski, MD, PhD, founder of the Burzynski Clinic and Burzynski Research Institute in Houston. I refer you to my original post for details, but in brief Dr. Burzynski claimed in the 1970s to have made a major breakthrough in cancer therapy through his discovery of anticancer substances in the urine that he dubbed “antineoplastons,” which turned out to be mainly modified amino acids and peptides. Since the late 1970s, when he founded his clinic, Dr. Burzynski has been using antineoplastons to treat cancer. Over the last 25 years or so, he has opened a large number of phase I and phase II clinical trials with little or nothing to show for it in terms of convincing evidence of efficacy. Worse, as has been noted in a number of places, high doses of antineoplastons as sodium salts are required, doses so high that severe hypernatremia is a concern.
Although antineoplastons are the dubious cancer therapy upon which Dr. Burzynski built his fame, they aren’t the only thing he does. Despite the promotion of the Burzynski Clinic as using “nontoxic” therapies that “aren’t chemotherapy” by “natural medicine” cranks such as Joe Mercola and Mike Adams, Dr. Burzynski’s dirty little secrets, at least as far as the “alternative medicine” crowd goes, are that (1) despite all of the attempts of Dr. Burzynski and supporters to portray them otherwise antineoplastons are chemotherapy and (2) Dr. Burzynski uses a lot of conventional chemotherapy. In fact, from my perspective, it appears to me as though over the last few years Dr. Burzynski has pivoted. No longer are antineoplastons the center of attention at his clinic. Rather, these days, he appears to be selling something that he calls “personalized gene-targeted cancer therapy.” In fact, it’s right there in the first bullet point on his clinic’s webpage, underlined, even! Antineoplastons aren’t even listed until the third bullet point.
But what is “personalized gene-targeted cancer therapy,” according to Dr. Burzynski? Here is how it is described:
Editor’s note: There is an update to this post.
An Apple fanboy contemplates computers and mortality
I’m a bit of an Apple fanboy and admit it freely. My history with Apple products goes way back to the early 1980s, when one of my housemates at college had an Apple IIe, which I would sometimes use for writing, gaming, and various other applications. Indeed, I remember one of the first “bloody” battle games for the IIe. It was called The Bilestoad and involved either taking on the computer or another opponent with battle axes in combat that basically involved hacking each other’s limbs off, complete with chunky, low-resolution blood and gore. (You youngsters out there will be highly amused at the gameplay here.) Of course, it’s amazing that nothing’s changed when it comes to computer games except the quality of graphics. Be that as it may, this same roommate was one of the first students to get a hold of the new Macintosh when it was released in early 1984. I really liked it right from the start but only got to play with it occasionally for a few months. After using a Macintosh SE to do a research project during my last year of medical school, I have used the Macintosh platform more or less exclusively, and the first computer I purchased with my own money was a Mac LC back in 1990 or 1991. Today, I have multiple Apple products, including my MacBook Air, my iPhone, and my old school iPod Classic, among others. Oddly enough, I do not have an iPad, but that’s probably only a matter of time, awaiting software that lets me do actual work on it.
All of this is my typical long-winded way of explaining why I was immensely saddened when I learned of Steve Jobs’ death last week. Ever since speculation started to swirl about his health back 2004 and then again in 2008, capped off by the revelation that he had undergone a liver transplant for a rare form of pancreatic cancer in 2009, I feared the worst. Last week, the end finally came. However, there is much to learn relevant to the themes of this blog in examining the strange and unusual case of Steve Jobs. Now, after his death five days ago, which coincidentally came a mere day after the launch of iCloud and the iPhone 4S, it occurs to me that it would be worthwhile to try to synthesize what we know about Jobs’ battle with cancer and then to discuss the use (and misuse) of his story. Of course, this is a difficult thing to do because Jobs was notoriously secretive and I can only rely on what has been published in the media, some of which is conflicting and all of which lacks sufficient detail to come to any definite conclusions, but I will try, hoping that the upcoming release of his biography by Walter Isaacson in couple of weeks might answer some of the questions I still have remaining, given that Isaacson followed Jobs through his battle with cancer and was given unprecedented access to Jobs and those close to him.
In the meantime, I speculate. I hope my speculations are sufficiently educated as not to be shown to be completely wrong, but they are speculations nonetheless.