Prostate

Aging is associated with a number of pathologic changes in the prostate. The most important of these are benign prostatic hyperplasia (BPH) and carcinoma of the prostate. The diagnosis of BPH is most often made on the basis of clinical assessment of prostate size (examination by means of a finger placed in the rectum) and symptoms such as reduced urinary flow rate and increased urinary frequency in the daytime or at night. Microscopic evidence of BPH is found in only 8 percent of forty year old men, in 50 percent of men aged fifty-one to sixty, and over 90 percent of men over the age of eighty, but only about one-third of these men have bothersome symptoms (Lepor; McConnell; Narayan; Weiss and Flair). Infrequently, BPH completely blocks urination and thereby causes kidney failure as the urine backs up through the bladder and uretes to damage the kidneys.

The major risk factors for BPH are age and normal male hormone (testosterone) status. The role of testosterone in BPH has been known since ancient times, when it was observed that boys castrated before puberty did not develop urinary retention and that castration provided relief for urinary obstruction in about one-third of cases.

Despite the observed association between prostate size and urinary symptoms, it is clear that factors other than the size of the gland are involved. Accordingly, obstruction can occur with relatively minor prostatic enlargement, presumably in men with weaker bladder contractility. Conversely, many men have large prostates but experience minimal symptoms.