Are more low-risk prostate cancers detected by repeated biopsy? A retrospective pilot study

Abstract

Purpose: We hypothesized that there might be a higher incidence of low-risk prostate cancer (PCa) in men diagnosed at a repeated biopsy. Thus, we investigated differences in clinicopathological results of PCa after primary and repeated biopsy.

Materials and methods: We retrospectively reviewed patients diagnosed with PCa at a primary or repeated biopsy from January 2004 to April 2011. Patients were stratified into primary biopsy and repeated biopsy groups. We analyzed prostate-specific antigen, clinical stage, Gleason score (GS), positive core ratio, and low-risk group by using D'Amico classification. We also investigated GS upgrading and upstaging after radical prostatectomy (RP).

Results: Among 448 primary and 37 repeated biopsy PCa patients, 82 (group 1) and 25 (group 2) underwent RP. The percentage of low-risk patients did not differ significantly between the groups. The positive biopsy core ratio was significantly lower in group 2 (p=0.009). The percentages of GS upgrading and upstaging were 42.7% and 47.6% in group 1, respectively (p=0.568), and 48.0% and 52.0% in group 2, respectively (p=0.901). In the analysis of low-risk patients, GS upgrading and upstaging were not significantly different between the groups (p=0.615 and p=0.959, respectively).

Conclusions: A lower positive core ratio may imply a small volume of PCa and possibly insignificant PCa in the repeated biopsy group. However, no significant differences were observed for the ratio of low-risk cancers, GS upgrading, or upstaging between the groups. Therefore, PCa diagnosed at a repeated biopsy is not an additional indication for active surveillance.

Keywords: Biopsy; Prostatectomy; Prostatic neoplasms.