The frequency of latent prostatic carcinoma in young males: the Japanese experience.

Prostates obtained at autopsy from five different ethnic groups were serially step-sectioned and examined microscopically using identical techniques and diagnostic criteria. The groups consisted of African-American and white males from the United States of America, Japanese immigrants in Hawaii, and Japanese men in Japan. The prostates were collected between 1965 and 1979. The fifth group consisted of newly collected prostates from indigenous Japanese between 1982 and 1986. The frequency of latent prostatic carcinoma from men under 50 years of age was compared to each other and with those from men over 50 years of age. Latent carcinoma was not found in men between 30 and 39 years old in any groups except indigenous Japanese men (6%) who died from 1982 to 1986. The frequency of latent carcinoma in the patients in fifth decade varied from 0 to 20%. Latent tumor was not found in the African-Americans in the fifth decade. There was an age-dependent increase in prostate cancer in all groups. The Japanese prostates from 1982 to 1986 had a higher rate of latent cancer than the ones from 1965 to 1979 in each decade. International comparison of the latent prostatic carcinoma from the patients under 50 years of age showed similar tendency as those from over 50 years old, Japanese men had a marked increase in the frequency of latent prostate cancer from 1965-1979 to 1982-1986. These data suggest that the prevalence of prostate cancer may be increasing worldwide.