Prognostic significance of primary Gleason pattern in Japanese men with Gleason score 7 prostate cancer treated with radical prostatectomy.

OBJECTIVES: To evaluate the significance of the primary Gleason pattern in patients with Gleason score (GS) 7 prostate cancer treated with radical prostatectomy.
MATERIALS AND METHODS: This study included 959 consecutive Japanese men who underwent radical prostatectomy without neoadjuvant therapies and were subsequently diagnosed as having GS 7 prostate cancer based on the modified International Society of Urological Pathology (ISUP) 2005 Gleason grading system.
RESULTS: Of these 959 patients, 666 (69.4%) and 293 (30.6%) had GS 3+4 and GS 4+3 tumors, respectively. There were significant differences in the prostate-specific antigen (PSA) level, biopsy GS, pathologic T stage, lymphatic invasion, microvenous invasion, and perineural invasion between these 2 groups. During the mean observation of 48.9 months, biochemical recurrence occurred in 211 patients (22.0%), and there was a significant difference in the biochemical recurrence-free survival between patients with GS 3+4 tumors and those with GS 4+3 tumors. Of several factors examined, biochemical recurrence-free survival was significantly associated with the PSA level, biopsy Gleason score, capsular penetration, seminal vesicle invasion, surgical margin status, lymphatic invasion, microvenous invasion, perineural invasion, and primary Gleason pattern, among which the PSA level, capsular penetration, seminal vesicle invasion, and surgical margin status, but not primary Gleason pattern, appeared to be independent predictors of biochemical recurrence.
CONCLUSIONS: Despite the lack of an independent significance, primary Gleason pattern based on the modified ISUP 2005 Gleason grading system is shown to be significantly associated with the biochemical outcome of Japanese men with GS 7 prostate cancer.