Carcinoma of the prostate in patients 70 to 79 years old

On step cross sections of the entire prostate gland in 100 patients aged 70 to 79, carcinoma was identified in 41. Of these, 17 were diffuse and 24 were focal. The site of origin of the diffuse carcinomas could not be ascertained though one half of the gland usually was involved more extensively. The location of focal carcinomas was usually at the periphery of the gland. While the microscopic patterns of diffuse and focal carcinomas were reasonably distinct, it appears that their biologic behavior is similar, and that focal carcinoma may be a stage in the development of diffuse carcinoma of the prostate.