Prostatic biopsy at Kawasaki Medical School: a prospective study of the results of transperineal biopsy over the past 13 years and the results of systematic 12-site biopsy using the transperineal and transrectal methods

The transperineal (TP method) and transrectal (TR method) approaches are used for systematic prostatic biopsy. At this institution, only the TP method was used until April 2003. The TR method was introduced in May 2003, and a prospective randomized study of the TP and TR methods was conducted. This report describes theresults and status of prostatic biopsy at this institution. Between May 1992 and October 2005, a total of 1,306 patients (including repeats) underwent prostatic biopsy at this institution. It was the initial biopsy in 1,144 cases. The TP method was used in 1,132 patients, and the number of biopsy cores was 6, 8, 10, and 12 in 432, 56, 262, and 382 patients, respectively. The TR method was used for 12‐core biopsy in 174 patients. From May 2003, a prospective randomized study of 12‐core biopsy by the TP and TR methods was conducted in 168 and 174 patients, respectively. The cancer detection rates by the TP method in all patients were 33.3%, 53.6%, 32.8%, and 42.7% for 6, 8, 10, and 12‐core biopsies, respectively. The cancer detection rate in patients with PSA 4.1‐10.0 ng/ mL (gray zone) was significantly higher for 12‐core biopsy (35.4%) than for 6‐core biopsies (21.9%) (p = 0.007). Cancer was detected in 163 of the 382 patients undergoing 12‐core biopsy by the TP method, while it was only detected in 140 patients by the examination of tissue specimens according to the protocol for 6‐core biopsy. In other words, the cancer detection rate was improved by 12‐core biopsy in 23 out of 163 patients (14.1%) (p< 0.001). Comparison of the TP and TR methods showed no statistically significant difference in the cancer detection rate in any of the patients between the TP (48.8%) and TR (53.4%) methods, and in the gray‐zone patients, no statistically significant difference was seen between the TP (37.5%) and TR (41.0%) methods. Aside from headache, presumably ralated to the different methods of anesthesia, no statistically significant differences were seen in the incidence of complications between the two methods. We consider that favorable results have been obtained using 12‐core biopsy at this institution. Since there are no differences in cancer detection rate or complications between the two methods, urologists should select either method according to their own skill and preference.