Metabolic epidemiology of prostatic cancer.

A review of the epidemiological evidence indicates that dietary fat very likely has an etiologic role in the development of prostatic carcinoma. While this effect may be mediated by way of altered hormonal action on the prostate, there is little supporting evidence from assays of plasma or urinary hormones in case-control studies or the investigation of high-risk and low-risk groups. The application of metabolic epidemiology to this problem is most likely to succeed by direct studies of the prostate gland, and the performance of relevant assays on prostatic fluid. Estradiol and estrone levels were found to be higher in prostatic fluid than in serum, whereas for prolactin the reverse was true. Testosterone concentrations were very low in prostatic fluid, perhaps because of the high degree of plasma protein binding. Preliminary data indicated that prostatic fluid estradiol and prolactin levels are elevated in some prostate cancer patients; estrone levels appear to be normal.