To date, prospective studies have demonstrated a low frequency of prostate cancer in association with testosterone-replacement therapy. A compilation of published prospective studies of testosterone- replacement therapy revealed only 5 cases of prostate cancer among 461 men (1.1 percent) followed for 6 to 36 months, a prevalence rate similar to that in the general population. These studies were performed in men with hypogonadism of varying causes and degrees, who may or may not have received testosterone treatment before the prospective studies. No follow-up data beyond 36 months are available.