Purpose: To investigate the differences in the cancer detection rate and pathological findings on a second prostate biopsy according to benign diagnosis, high-grade prostatic intraepithelial neoplasia (HGPIN), and atypical small acinar proliferation (ASAP) on first biopsy.
Materials and methods: We retrospectively reviewed the records of 1,323 patients who underwent a second prostate biopsy between March 1995 and November 2012. We divided the patients into three groups according to the pathologic findings on the first biopsy (benign diagnosis, HGPIN, and ASAP). We compared the cancer detection rate and Gleason scores on second biopsy and the unfavorable disease rate after radical prostatectomy among the three groups.
Results: A total of 214 patients (16.2%) were diagnosed with prostate cancer on a second biopsy. The rate of cancer detection was 14.6% in the benign diagnosis group, 22.1% in the HGPIN group, and 32.1% in the ASAP group, respectively (p<0.001). When patients were divided into subgroups according to the number of positive cores, the rate of cancer detection was 16.7%, 30.5%, 31.0%, and 36.4% in patients with a single core of HGPIN, more than one core of HGPIN, a single core of ASAP, and more than one core of ASAP, respectively. There were no significant differences in Gleason scores on second biopsy (p=0.324) or in the unfavorable disease rate after radical prostatectomy among the three groups (benign diagnosis vs. HGPIN, p=0.857, and benign diagnosis vs. ASAP, p=0.957, respectively).
Conclusions: Patients with multiple cores of HGPIN or any core number of ASAP on a first biopsy had a significantly higher cancer detection rate on a second biopsy. Repeat biopsy should be considered and not be delayed in those patients.
Keywords: Biopsy; Prostate neoplasms; Prostatic intraepithelial neoplasia.