Diet and medications may assist prostate Ca prevention

Recent investigations of medications, diet, and the molecular understanding of prostate cancer are defining potential prevention strategies for the disease and herald a new stage in its management, according to a review to be published in Cancer.

Neil Fleshner, MD, and Alexandre Zlotta, MD, of the University of Toronto, reviewed the published literature to evaluate the progress toward developing an evidence-based prostate cancer prevention strategy. Current studies using existing drugs to prevent cancer have found that androgen-suppressing 5-alpha-reductase inhibitors such as finasteride (Proscar) and dutasteride (Avodart), and the selective estrogen receptor modifier toremifene (Fareston) have showed promise in reducing the number of cancers at biopsy in men.

Other studies are currently investigating the role of reduced fat intake and dietary supplements in preventing prostate cancer. In one study of selenium, the incidence of prostate cancer was reduced by 49% over 10 years. Other nutritional approaches, such as green tea, show conflicting results for prevention. Meanwhile, studies of some approaches, like soy and vitamin D, are ongoing. Evidence for the use of vitamin E in reducing disease rates is promising, but mild safety concerns at the high doses currently tested raise caution.

The authors point to studies that suggest prostate cells become malignant in men in their 20s and 30s.

"Unless we intervene with men in their early 20s, prevention in the context of prostate cancer refers to a slowing of the growth of existing prostate cancer cells so that they never harm the host,” they concluded.

The next 5 years will be a dynamic period in evaluating several prevention strategies because "a host of phase III studies that have been completed and analyzed or completed accrual" will be published, the authors noted.

But in the future, according to the authors, understanding the molecular pathways that develop, sustain, and progress malignant cells in the prostate will be critical in the development of new strategies. Data already suggest novel uses of statins and insulin-modulating drugs, they noted.