Comparison of Localized High Volume Tumor and Locally Advanced Low Volume Tumor after Radical Prostatectomy according to Risk Classification

ABSTRACT

PURPOSE: To investigate the percentage of pathologic tumor volume (pTPV) among patients who underwent radical prostatectomy (RP). MATERIALS AND METHODS: We reviewed 3,080 patients who underwent RP between September 2003 and March 2015 and with a postoperative follow-up for more than 1 year. The patient population was stratified into 4 disease risk groups according to tumor stage and pTPV (T2 low volume [T2LV], T2 high volume [T2HV], T3 low volume [T3LV], and T3 high volume [T3HV]). Probability of biochemical recurrence (BCR)-free survival was determined using Kaplan-Meier curves. pTPV was evaluated by Multivariate Cox proportional hazard analysis for predicting BCR. Subgroup analyses were performed according to preoperative risk. RESULTS: The median prostate-specific antigen (PSA) was 7.87 ng/mL, and pTPV was 10%. Among a total of 2,964 patients, T2LV had 1,473 (49.7%), T2HV was 598 (20.2%), T3LV with 199 (6.7%), and T3HV was 694 (23.4%). When comparing T2HV and T3LV, Gleason score and positive surgical margin rate was higher in T3LV. During a 50-month follow-up, BCR-free survival rate was higher in the T2HV group (p<0.001). pTPV was a significant factor to predict BCR in multivariate Cox analysis. In subgroup analyses, T2HV group had similar BCR-free survival rates to T3LV group in the preoperative high risk group while pTPV was significant in the high risk group. CONCLUSIONS: pTPV was a significant predictor of BCR among prostate cancer patients after RP, however T2HV had favorable BCR results. Among patients with a preoperative high PSA and Gleason score, T2HV had similar BCR results to T3LV.