COMPARISON LOCALIZATION RESULTS BASED ON PROSTATE BIOPSY SPECIMENS WITH RESULTS BASED ON RADICAL PROSTATECTOMY...

(Objective) The Clinical Practice Guidelines for Prostate Cancer (2012 Edition) recommend a 10- to 12-core biopsy comprising six standard cores from the apex, midgland, and base as well as cores from six peripheral zones (PZ) outside these sites. In this study, we compared localization results (mapping) based on 12-core prostate biopsy specimens from the six standard sites and six PZ outside these sites with results based on radical prostatectomy specimens. (Subjects and methods) Of the 208 patients with prostate cancer who underwent radical prostatectomy at our hospital between January 2011 and July 2014, the 139 who had a 12-core biopsy before surgery were included in this study. Prostate needle biopsies were performed transrectally and the same pathologist evaluated preoperative biopsy specimens and resected pathology specimens. Patient age ranged from 52 to 77 years (median: 68 years). Prostate-specific antigen levels at the time of biopsy ranged from 3.1 to 84.7 ng/ml (median: 7.3 ng/ml) and the weight of excised tissue ranged from 17 to 90 g (median: 37 g). The surgical method was laparotomy in 63 cases, laparoscopy in 12 cases, and robot-assisted in 64 cases. The preoperative T classification was cT1c in 84 cases, cT2a in 29 cases, cT2b in 15 cases, and cT2c in 11 cases. The preoperative Gleason score was 3+3=6 in 36 cases, 3+4=7 in 48 cases, 4+3=7 in 33 cases, 4+4=8 in 9 cases, 4+5=9 in 11 cases, and 5+4=9 in 2 cases. The postoperative T classification was pT2a in 38 cases, pT2b in 12 cases, pT2c in 17 cases, pT2+in 20 cases, pT3a in 47 cases, and pT3b in 5 cases. The postoperative Gleason score was 3+3=6 in 19 cases, 3+4=7 in 60 cases, 4+3=7 in 39 cases, 4+4=8 in 1 case, 4+5=9 in 14 cases, 5+4=9 in 5 cases, and 5+5=10 in 1 case. (Results) The concordance rate for detection of cancer (localization) in the 12 sites of the preoperative biopsy and the same sites of resected specimens was 59.2% (median: 7.11/12). Furthermore, the Gleason score of the resected specimen was higher than the preoperative score for 79 patients (56.8%) and 63 of the 88 patients (71.6%) whose cancer was classified as unilateral on the basis of the preoperative biopsy were found to have cancer on the other side as well when the resected specimen was examined. (Conclusion) The results suggest that localization is not always consistent between positive biopsy sites and sites in resected specimens. This indicates that when attempting to localize prostate cancer preoperatively, it is necessary to use other tests such as MRI as well.