The presence of atypical small acinar proliferation in prostate needle biopsy is predictive of carcinoma on subsequent biopsy

OBJECTIVE: To determine the clinical significance of nondiagnostic small acini showing cellular atypia (atypical small acinar proliferation) in prostatic biopsies of patients with clinical findings suggestive of malignancy. PATIENTS AND METHODS: Of 331 patients who underwent thin-core biopsy of the prostate over a 30-month period, 21 (6.3%) had atypical histological features, and of these 17 underwent repeat biopsy. In addition, a further 20 patients with normal histology underwent repeat biopsy for persistent abnormal clinical findings. The incidence and Gleason score of carcinomas subsequently diagnosed in the two groups were compared. The predictive significance of patient age, prostate specific antigen (PSA) level and digital rectal examination (DRE) findings were compared between both patient groups, those in each group subsequently found to have carcinoma, and between patients with malignant or normal repeat biopsies who had either atypical or normal initial biopsies. RESULTS: Nine patients with atypical histology and four with normal histology on initial biopsy were found to have carcinoma on subsequent biopsy (P = 0.036). The site of carcinoma diagnosed in the repeat biopsy frequently differed from that of the initial atypical biopsy. The Gleason primary pattern was not significantly different between the groups. Neither patient age, PSA level nor DRE findings differed between patients with initial normal or atypical biopsy, or in these groups for those in whom carcinoma was subsequently diagnosed. These clinical features did not distinguish between those with carcinoma or normal findings on repeat biopsy who had an initial atypical biopsy, while only PSA level varied significantly in patients with normal or malignant repeat biopsy in the group with an initial normal biopsy. CONCLUSION: The presence of atypia on initial biopsy is a strong predictor of malignancy in subsequent biopsy specimens.