Value of the New 5-Tiered Prostate Cancer Grade Group System on Predicting Oncological Outcomes for Radical Prostatectomy Population in Korea

ABSTRACT

PURPOSE: We evaluated the prognostic value of the 5-tiered grade group in Korean patients who underwent radical prostatectomy. MATERIALS AND METHODS: Between 1996 and 2016, a number of 2,883 consecutive patients who underwent radical prostatectomy were included for the analysis. The impacts of biopsy and pathologic grade group on predicting biochemical recurrence (BCR) were assessed using multivariate analysis. Median follow-up duration was 49.0 months. RESULTS: Mean age was 66.5 years and prostate-specific antigen (PSA) was 11.8 ng/mL. Prostate cancer was locally advanced on magnetic resonance imaging in 13.4%. Biopsy grade group was as follows: 1 (46.8%), 2 (19.8%), 3 (14.2%), 4 (14.1%), and 5 (5.1%). Pathology stage was ≤T2 in 63.6%, T3a in 26.0%, and T3b/T4 in 10.4% patients. Pathologic grade was as follows: 1 (31.3%), 2 (37.9%), 3 (20.2%), 4 (4.7%), and 5 (5.1%). In multivariate analysis using biopsy-related variables, biopsy grade group (1, reference; 2, hazard ratio [HR], 1.771; p=0.001; 3, HR, 2.736; p < 0.001; 4, HR, 2.966; p < 0.001; 5, HR, 3.707; p < 0.001) was associated with BCR-free survival, PSA level and % positive core. In multivariate analysis using pathologic outcomes, pathologic grade group (1, reference; 2, HR, 1.882; p < 0.001; 3, HR, 3.352; p < 0.001; 4, HR, 3.890; p < 0.001; 5, HR: 3.118, p < 0.001) was associated with BCR-free survival in addition to pathologic stage and positive surgical margin. CONCLUSIONS: New 5-tiered grading system could be useful for predicting oncological outcomes in Korean patients although its role for distinguishing outcomes between patients with grade groups 3–5 need to be validated before wide application of this grade system in Korea.