Incidental carcinoma of the prostate. How much sampling is adequate?

A prospective study of 386 consecutive transurethral prostatic resections from 383 patients with clinically benign glands was undertaken to determine the optimal sampling of chips required for the histologic detection of all clinically significant prostatic carcinomas. Cancers were graded according to two systems and staged by counting involved chips as well as estimating volume density. All Stage A2 prostatic carcinomas were detected by histologic examination of 6 g of randomly selected chips. Although additional tumors were detected in direct proportion to the amount of tissue examined, they were small, well-differentiated, Stage A1 lesions. Histologic sampling of 12 g of randomly selected prostatic chips detected almost 90% of incidental carcinomas, including all clinically significant neoplasms.