Stratification of patients with intermediate-risk prostate cancer

Abstract

Objective: To identify an appropriate risk stratification system for intermediate-risk prostate cancer (PCa).

Patients and methods: We reviewed the data on 1559 patients who were treated with radical prostatectomy (RP) at our institution between 2005 and 2013 and classified them according to National Comprehensive Cancer Network (NCCN) risk groups. For our analyses, intermediate-risk PCa was designated as unfavourable intermediate-risk PCa if it met at least one of the following two criteria: biopsy Gleason score 4 + 3 and/or presence of ≥ 2 intermediate-risk criteria. All other men with intermediate-risk PCa were designated as having favourable intermediate-risk disease. Postoperative outcomes, including biochemical recurrence (BCR)-free survival, were calculated and compared using the log-rank test and Cox proportional hazards model.

Results: In multivariable analysis, biopsy Gleason score 4 + 3 and multiple (≥ 2) intermediate-risk criteria were observed to be independent predictors of BCR risk among men in the intermediate-risk group undergoing RP. The favourable intermediate-risk group had a significantly higher 5-year BCR-free survival compared with the unfavourable intermediate-risk group (87.5 vs 66.5%; P < 0.001). The unfavourable intermediate-risk group had significantly higher 5-year BCR-free survival than the high-risk group (66.5 vs 47.9%; P < 0.001) while the favourable intermediate-risk group had significantly lower 5-year BCR-free survival than the low-risk group (87.5 vs 93.5%; P = 0.002).

Conclusions: A marked heterogeneity exists in the biochemical outcomes of contemporary patients with intermediate-risk PCa who undergo definitive RP. According to biopsy Gleason score and number of intermediate-risk criteria present, the intermediate-risk group should be sub-divided into those with favourable and unfavourable intermediate-risk disease.

Keywords: Gleason grade; intermediate-risk; prostate; prostatectomy; prostatic neoplasms; risk stratification.