Q. I have been treated for prostate cancer. My oncologist has recommended that I take the diabetes drug metformin and the cholesterol medication rosuvastatin to reduce my risk of recurrence.
When I saw my family doctor and said I am taking these drugs, he was surprised. He had never heard of this use and said it was off-label. Is there any evidence that these drugs would be helpful against cancer?
A. There are studies to suggest that the diabetes drug metformin could have anti-cancer activity. An overview published in Investigative and Clinical Urology (May, 2016) noted that “Use of metformin has been shown to be associated with decreased incidence and improved outcomes of prostate, bladder, and kidney cancer.”
Statins and an Anticancer Effect?
There are biological reasons to expect statins might also block prostate cancer, but the research so far has been inconclusive (Nutrition and Metabolic Insights, online July 14, 2016). An Australian study is underway to determine if metformin and atorvastatin together can affect the course of localized but aggressive prostate cancer (Contemporary Clinical Trials, online June 28, 2016). The answer won’t be apparent for a few more years.
Before anyone asks about either metformin or rosuvastatin (Crestor) it is important to know about potential adverse drug reactions:
Metformin Side Effects:
- Digestive upset, diarrhea, nausea, vomiting, indigestion, flatulence, GI pain
- Vitamin D depletion
- Lactic acidosis (confusion, anxiety, headache, fatigue, weakness, nausea, rapid pulse, irregular heart rhythms, sweating, clammy skin, rapid breathing
Crestor (rosuvastatin) Side Effects:
- Muscle aches, muscle pain, muscle cramps, weakness
- Abdominal discomfort, nausea, diarrhea
- Blood sugar elevation, diabetes
- Back pain
- Flu-like symptoms
- Skin reactions, itching, rash
- Liver damage
- Forgetfulness, memory problems
We look forward to the day when we have more data on the benefits and risks of metformin and statin-type drugs against prostate cancer. It would be very good news indeed if such drugs could prevent recurrence of this potentially deadly cancer.