Metformin and Statins for Prostate Cancer

Many times throughout my career treating prostate cancer patients, I have periodically been asked by patients, “What is it exactly that you do?  Surgeons (urologists) operate, and radiation doctors give radiation, but what does a prostate oncologist do?”  Typical daily patient care includes rendering medical advice and prescribing medications.  So some patients see me as a “pill pusher.” I’m not sure I understand this mentality.

After all, prescribing pills only generates profits for pharmaceutical companies, not for my practice.  Even so, at the risk of being misunderstood, I need to defend using two widely-prescribed types of pills for men with prostate cancer:  Metformin, a generic diabetes pill, and cholesterol pills (statins).

Diet impacts prostate cancer progression.  I have seen my patients effectively suppress rising PSA levels by adhering to a stringent vegan or macrobiotic diet.  My belief in the importance of diet was further solidified when T. Colin Campbell published The China Study, a book that showed a strong connection between increased animal protein intake and higher cancer rates. 

How can diet make such a big impact?  We don’t have all the answers but there are some very logical suppositions.  First consider that cancer cells cause harm by cellular multiplication and tumor growth. The enlarging tumors spread through the body creating organ malfunction.

Anything that grows, can be expected to grow faster stronger? when “well fed.”   Diets high in animal protein promote cellular growth.  Baby boomers can recollect the growth effects of diet by looking at the average height of our parents and grandparents.  My grandfather who grew up on a grain-based diet was 5’8’’.

 My father who grew up on a hearty American diet with lots of milk and red meat was 6’4.”   A diet high in animal protein promotes growth because it provides all the necessary amino acids for the construction of new cells.  Animal protein also contains fat, a potent energy source.  For example, a “lean” hamburger is over 50% fat.  High protein diets also increase the level of insulin in the blood.  Elevated insulin levels drive sugar and protein uptake into the cancer cells, further promoting growth.   Dietary cholesterol is not only a type of “fat,” but it is also a hormonal precursor and a building block for DHEA and testosterone, which are hormones that prostate cancer needs to survive. 

Unfortunately, only a few of us have the capability of following a strict vegan diet.  It’s a lot of work and requires constant self-denial.  However, certain medications can mimic a diet that lowers fat and suppresses insulin levels. 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, such as Lipitor and Crestor, dramatically lower cholesterol levels.  Numerous studies have reported higher cure rates in prostate cancer patients receiving radiation who are also treated with statins compared to radiation-treated patients who do not receive a statin.

Regular exercise has also been shown to prolong 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.  Careful monitoring can detect problems at an early stage, so the medication can be stopped before there is any lasting harm.  In my experience, following a rigorous, low protein diet has beneficial anticancer effects.  However, additional benefits from modern pharmaceuticals should not be ignored.  In men with the more serious types of prostate cancer, taking an FDA-approved pill, while using careful precautions against potential side effects, it far more likely to be beneficial than harmful.   

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