Conditional Survival and Time of Biochemical Recurrence of Localized Prostate Cancer in Japanese Patients Undergoing Laparoscopic Radical Prostatectomies.

Abstract

Using conditional survival (CS) analysis, we investigated whether the duration of survival without biochemical recurrence (BCR) of prostate cancer after laparoscopic radical prostatectomies (LRP) affected the BCR rate. We also investigated the impact of well-known risk factors for BCR. Between 2002 and 2014, 627 consecutive patients underwent LRPs at our institution. Prostate-specific antigen (PSA) concentrations above 0.2 ng/mL were defined as BCR. Conditional BCR-free survival rates were determined through Kaplan-Meier analysis. Assessment of potential BCR risk factors was performed using a Cox proportional hazard analysis. The 10-year BCR-free rates after LRP increased to 82.4%, 84.5%, 86.6%, 90.1%, and 94.7% in patients surviving 1, 2, 3, 5, and 7.5years without BCR, respectively. Multivariate analyses of age, PSA concentrations, neoadjuvant therapy, and pathological findings were performed for all patients. In all patients, positive surgical margins (PSM) and Gleason Grade Groups (GG) ≥ 4 were independent risk factors for BCR (p < 0.001, hazard ratio [HR] = 2.45; and p < 0.001, HR = 2.83, respectively,). Similarly, PSM and GG ≥ 4 were significant risk factors in patients surviving 1-5years without BCR. No clear risk factors were observed in patients surviving > 5years without BCR after LRPs. The BCR-free rate increased with time after LRP. It is recommended that patients with PSM, GG ≥ 4, or with both factors are strictly monitored for 5years postoperatively. CS analysis is particularly useful for predicting the postoperative course of patients.