Carcinoma of the prostate: results of post-irradiation biopsy.

One hundred and forty-six patients with clinically localized carcinoma of the prostate were surgically staged and treated with external beam irradiation to the prostate and to the lymph node-bearing areas. Sixty-four (44%) of these patients had needle biopsy of the prostate 18 months or more following completion of therapy. Thirty-nine (61%) of the biopsies were interpreted as positive and 25 (39%) as negative. Twenty-eight (72%) of the 39 patients with a positive biopsy have subsequently developed metastases as compared to only 6 of 25 (24%) of the patients with a negative biopsy. It is concluded that an apparently positive postirradiation biopsy is likely to indicate active disease and identifies patients at a higher risk for development of metastases. Other details of staging, grading, and outcomes that compare these two groups are discussed.