Can medications or supplements for other medical conditions affect prostate cancer outcomes?

This study reviewed evidence on the use of medication and supplements for additional medical conditions on prostate cancer mortality. Authors concluded that commonly used medications and supplements can influence prognosis among prostate cancer patients. 

Prostate cancer is more common among older men. Older men are also more likely to have other medical conditions and take medication or supplements for those conditions. Common additional medical conditions are cardiovascular disease (disease of the heart and blood vessels) and metabolic diseases (diabetes, high blood pressure, weight gain, high blood sugar, and high cholesterol levels). Some studies have suggested that the medications used for these conditions may affect prostate cancer outcomes. 

The aim of this study was to review evidence on the use of medication and supplements for additional medical conditions on prostate cancer outcomes.

An analysis of 6 separate studies showed that the use of statins (cholesterol-lowering drugs) reduces the risk of prostate cancer mortality by 24%. 1,791 deaths due to prostate cancer were observed in a large study involving 11,772 men with localized prostate cancer. Results showed that the risk of prostate cancer mortality was 24% lower among statin users. Men taking statins before prostate cancer diagnosis showed the greatest benefit.

One study involving 3,837 diabetic men with prostate cancer examined the effects of metformin (Glucophage) use on cancer mortality. Analysis showed that each additional 6 months of metformin use reduced the risk of prostate cancer mortality by 24%. Insulin (hormone that controls blood sugar levels) therapy has previously been associated with advanced prostate cancer stage. However, more studies on the effects of insulin are needed.

Preventative use of acetylsalicylic acid (aspirin) was associated with a 19% reduced prostate cancer mortality in a study of 1,010 deaths from high-risk or metastatic prostate cancer. One analysis found that lower prostate cancer mortality appeared to be limited to aspirin users with high-risk cancers.

Men who took more than 400 mg per day of supplementary calcium had a 51% higher risk of fatal prostate cancer. In a high-quality study of 148 prostate cancer deaths, the use of multivitamin and mineral supplements was not associated with prostate cancer mortality. However, multivitamin use above the recommended daily dose did increase the risk of prostate cancer death. 

The use of blood pressure-lowering drugs was associated with reduced risk of prostate cancer mortality. The risk was reduced by 22% for angiotensin-converting enzyme (ACE) inhibitors and by 21% for angiotensin II receptor blockers (ARBs).

Researchers concluded that commonly used medications and supplements can significantly affect prostate cancer outcomes. 

Many of the studies included were observational. Studies that randomly assign patients to treatment groups are usually more reliable.