Necessity of repeat biopsies in men for suspected prostate cancer.

Abstract

The indications for repeat prostate needle biopsy in men whose initial biopsy results revealed no evidence of cancer are not defined. We retrospectively studied 218 consecutive cases of men undergoing prostate biopsies for suspected cancer. Men in whom cancer was found on repeat biopsy were compared with others with regard to age, digital rectal examination, serum prostate-specific antigen (PSA) concentration, prostate volume, PSA density, PSA slope and the frequency of prostatic intraepithelial neoplasia (PIN) on initial prostate biopsy. Of the 114 cancers detected, 99 (87%) were diagnosed on initial biopsy and 15 (131%) were diagnosed on repeat biopsy. Mean PSA concentration and mean PSA density were significantly higher in patients with cancer on initial biopsy than on repeat biopsy (P<0.05), but they were similar among patients with and without cancer on repeat biopsy. The PSA slope showed a more progressive increase in patients with cancer on repeat biopsy than in those patients without cancer at 6 month intervals. Of the 218 patients undergoing prostate biopsy, seven (3.2%)) were identified with high grade PIN but without concurrent prostate cancer. Prostate cancers were detected in two of these seven patients (29%) on repeat biopsy. Serum PSA levels and PSA density did not provide useful predictive information about the indications of repeat biopsy. We conclude that men with a more progressive increase in PSA levels at 6 months intervals and high grade PIN on prostate needle biopsy should undergo repeat sampling to exclude missed cancer.