Characterization of minute adenocarcinomas of prostate at radical prostatectomy.

OBJECTIVES To characterize minute prostate cancer seen at radical prostatectomy. With aggressive screening and more extensive biopsy sampling, we have increasingly seen these cancers at radical prostatectomy. METHODS We examined radical prostatectomy specimens submitted in total for minute cancer. RESULTS During the past 1.5 years, 78 prostates (5.2%) had either no cancer (2 cases) or contained between one and six foci of organ-confined carcinoma (76 cases) measuring 6 mm or less, with a Gleason score of 6 or less. The mean prebiopsy serum prostate-specific antigen level was 5.8 ng/mL, and 84.6% of the patients had undergone biopsy because of an elevated prostate-specific antigen level. Of these patients, 40% had had either benign or atypical diagnoses on prior biopsies, and 43% had only minute (0.5 mm or less) foci of carcinoma on biopsy. The radical prostatectomy specimens had a mean of two cancer foci measuring, on average, 3 mm in the greatest dimension. In 85% of the cases, the side of the positive biopsy matched the side of the carcinoma found at radical prostatectomy; 81.5% of cases had high-grade prostatic intraepithelial neoplasia immediately adjacent to the cancer. CONCLUSIONS The incidence of minute carcinoma of the prostate has increased from 0.5% in 1988 to 5.2% in the current study. The patients often had moderately increased prostate-specific antigen levels and minute foci of carcinoma on biopsy. These small tumors at radical prostatectomy are usually discovered by fortuitous biopsy that is often preceded by other biopsies with noncancerous diagnoses. Patients with the above clinical and biopsy findings should be counseled about the possibility of finding only minute foci of carcinoma at radical prostatectomy and may want to consider watchful waiting.