The co-authors of Invasion of the Prostate Snatchers, blog alternate posts weekly. We invite you to post your comments.

Tuesday, May 12, 2015

Metformin and Statins for Prostate Cancer


As an internist and an oncologist, throughout my long career treating prostate cancer patients, I have periodically been asked by patients, “What do you do?  Surgeons (urologists) operate, and radiation doctors give radiation, but what do prostate oncologists do?”  My day-to-day, bread and butter is giving medical advice and prescribing oral medications. Unfortunately, I think this leads to some patients seeing me as a “pill pusher.” As such, I think I need to explain my motives for recommending the use of metformin and statins to my patients with prostate cancer.

One of the things that the last 20 years of my career treating prostate cancer has taught me is that a good diet has a favorable effect on inhibiting prostate cancer progression.  What converted me from a nonbeliever to a believer?  My patients.  A number of men have come to me through the years whose PSA was rising after surgery and who subsequently embarked on stringent vegan or macrobiotic diets. Lo and behold, as long as they stayed on their diets their PSA levels would stabilize. Subsequently, T. Colin Campbell published a very convincing book called The China Study that evaluated the connection between increased animal protein intake and cancer rates.  His findings conclusively demonstrated that high animal protein intake increases cancer risk.

How can diet make such an impact?  We don’t have all the answers but there are some very logical suppositions.  First, cancer cells “hurt” people by the process of cellular multiplication, ultimately spreading throughout the body and causing organ malfunction. It’s logical to assume that “better fed” cancers, the ones that get plenty of protein and energy, will grow faster and better than cancers that are relatively deprived.  Animal protein not only provides all the necessary amino acids for the construction of new cells, animal protein is invariably accompanied by substantial amounts of a potent energy source—fat (People forget that the average hamburger is over 50% fats). High protein diets also increase the level of insulin in the blood. And high insulin levels drive sugar and protein uptake into the cancer cells, further promoting growth. And lastly, dietary cholesterol is not only a type of “fat,” but it is also a hormonal precursor, a building block for DHEA and testosterone.

Unfortunately, few of us have the ability to follow strict vegan diets. It’s a lot of work and requires constant self-denial.  Certain medications, however, can achieve some of the same effects. Metformin, a generic medication approved for the treatment of diabetes, suppresses insulin levels in the blood. Studies in diabetic men with prostate cancer who are treated with metformin have shown lower prostate cancer mortality rates compared to diabetic men who are treated with other types of diabetic medications besides metformin.  Statins pills, medications such as Lipitor and Crestor, dramatically lower cholesterol levels.  Numerous studies have reported higher cure rates in prostate cancer patients receiving radiation who are treated with statins compared to radiation-treated patients who don’t receive a statin.

Regular exercise prolongs life in cancer patients.  If we had a pill that could accomplish what exercise can do—improved energy levels, sleep, digestion, memory, longevity and less depression—everyone would take it.  Many patients are lukewarm about prescription pills like metformin and statins, probably mainly due to concerns about side effects.  But side effects can be anticipated with careful monitoring.  When a medication side effect occurs it can be detected early and when the medication is stopped the problem is almost always resolved.  Following a rigorous macrobiotic diet for the rest of your life is beyond the reach of most of us. Taking an FDA-approved pill, while using careful precautions against potential side effects, is achievable for almost all of us. 

Register now! Join PCRI, September 11-13, 2015 for The 2015 Prostate Cancer Conference - providing educational sessions on the latest prostate cancer treatment options, lifestyle changes, and quality of life issues presented by world-renowned physicians and researchers. Hosted at The Los Angeles Airport Marriott. For more information:


Anonymous said...

Campbell's China study is epidemiological in nature and these types of studies, especially nutritional studies, are not usually worthwhile. At very best, they can show correlation and not causation. Campbell's own data doesn't support his conclusions. See Denise Minger's analysis here:

Campbell also selectively leaves out data that contradicts his conclusions such as the county in China that ate 45% fat and 135 grams of protein, yet were healthy with low rates of cancer.

That doesn't mean that food can't have an impact, and it seems reasonable that high insulin levels and IGF-1 levels will help fuel cancer growth. I agree moderating protein can help keep insulin levels down, as well as keeping the starchy carbs down too.

Fortunately more practitioners are on board with the concept that dietary cholesterol doesn't lead to high serum cholesterol.

Charles "Snuffy" Myers is advocating a higher fat diet too and I'm sure isn't as Vegan as Campbell would like. (unfortunately he has a video post confusingly comparing fish oil with saturated fats like coconut oil for cooking. Nobody said these things are mutually exclusive. Nobody cooks with fish oil, but the point is that saturated fat is not unhealthy and you can still benefit from fish oil and Omega-3's.

Jan said...

I suggest you read Denise Minger's critique of The China Study