Nutrition and pharmacological treatment for prevention of prostate cancer

Prostate cancer is the most common neoplasm and the second cause of cancer death. It is an excellent target for primary chemopreventive strategies for the following reasons: it is highly prevalent and has a long latency period, there are identifiable risk factors and a precursor lesion and it produces a biochemical marker (serum PSA) which can serve as an intermediate end point in chemoprevention studies. The goal of primary prevention strategies is to prevent development of clinical life-threatening neoplasms in asymptomatic patients with no evidence of clinical disease. Identification of populations at risk for developing cancer is the cornerstone of chemoprevention. Well-established risk factors for prostate cancer include African-American race, older age and family history. Data on diet and obesity are less clearly defined. Since high grade prostatic intraepithelial neoplasia (PIN) is an early predictor of prostate cancer, preventive strategies focusing on men with high grade PIN are being explored. It was demonstrated that finasteride could significantly reduce prostate cancer in asymptomatic men with normal PSA and no abnormalities on rectal examination. Elevated prostaglandin levels, and upregulation of cyclooxygenase-2 (COX-2) are found in prostate cancer cell lines. There is some epidemiologic evidence that regular use of NSAIDs, which inhibit COX-2, may be associated with a lower risk of prostate cancer. In the field of nutrition, data from prospective large-scale studies demonstrated that increased consumption of lycopene-rich tomato-based foods referred to a reduction in the risk for prostate cancer. Vitamin E was also found to reduce prostate cancer risk. Prospective data showed that vitamin D has an inhibitory effect on prostate cancer development while increased calcium consumption, independent from dietary intake, might increase the risk. Dietary fat intake, particularly from animal sources, may also increase the risk for prostate cancer. Whether this effect is strictly due to the already identified compounds or to other compounds, remains to be explored. Further study will hopefully help to establish a core set of nutritional and dietary factors that can positively or negatively affect prostate cancer development, as well as a set of pharmacologic agents that can reduce the risk of prostate cancer development and/or progression in selected patients.