How much of your chance to develop cancer is under your control? Not much, unless you have a family history of particular cancers or you are still smoking, sunbathing without sunscreen, or are obese, a startling study in the journal Science Rick and I discuss on PodMed this week reveals. Authors Bert Vogelstein and Cristian Tomasetti analyze data relative to mutations, known to be the cause of cancer, and how they are stimulated to occur, and find that the majority of mutations are random, accumulating over time until in some cases, they cause a cancer to develop. How did they reach such a conclusion?
Tomasetti and Vogelstein studied the "relationship between the number of normal stem cell divisions and the risk of 17 cancer types in 69 countries throughout the world." Previous research had demonstrated that the greater the number of divisions cells of a tissue undertook the greater the risk of developing cancer. This work demonstrates that for some tissues, for example, lung, environmental exposures, in particular smoking, produce about two-thirds of the cancers, but for the majority of all cancers, two-thirds or more are the result of random mutations. That means that our ability to control cancer development by lifestyle choices is very limited, and of course to control cancers due to inherited genes, which account for about 5% of all cancers, is nonexistent.
What can we do then? Both authors opine that first, most people with cancer should jettison the guilt, (not those who continue to smoke, however!) since we can't control random. And we should focus our efforts as a research and medical care community on early detection, since the best chance to cure cancer lies in finding it before it becomes problematic. This is increasingly possible with the integration of imaging, genetic assessments, and screening. Finally, they propose that random mutations are the engine of evolution and are this necessary, so rueing the existence of this phenomenon is a lot like hating a pig for its grunt.
Other topics this week include Intradiscal Glucocorticoid Injection for Patients With Chronic Low Back Pain Associated With Active Discopathy: A Randomized Trial, in Annals of Internal Medicine, Direct-to-Consumer Advertising of Androgen Replacement Therapy in JAMA, and Two Paradigms for Endovascular Thrombectomy After Intravenous Thrombolysis for Acute Ischemic Stroke in JAMA Neurology. Until next week, y'all live well.