Conditional Disease-free Survival After Radical Prostatectomy: Recurrence Risk Evolution Over Time

Abstract

To assess changes in conditional disease-free survival (DFS) rates after radical prostatectomy (RP) and how the impact of well-known prognostic factors evolves over time. There were 2813 patients treated with RP and postoperatively followed with clinical and prostate-specific antigen assessments. Estimation of conditional survival (CS) probabilities used the Kaplan-Meier method. Multivariable Cox regression model was used to calculate proportional hazard ratios for prediction of DFS after stratification by prognostics characteristics. The 5-year DFS rate was 71.2%. The DFS rate 5 years after RP increased to 77.4% (+8.7%), 82.1% (+15.3%), 88.0% (+23.6%), and 94.0% (+32.0%) for patients surviving without recurrence 1, 2, 3, and 4 years after RP, respectively. This represented a relatively stable survival gain per survived year ranging from 5.6% to 8.7%. The conditional 5-year DFS improves mainly for disease-free surviving patients with adverse pathologic factors. Among patients with pT3b-4 disease, the probability of surviving without recurrence to year 5 increased from 20.7% at the time of presentation to 78.9% for patients surviving 4 years without recurrence (+281%) as compared to +12.5% in pT2 disease. The impact of Gleason score and pT stage on CS estimates remained stable over time. Findings were confirmed upon multivariable analyses. The period elapsed from RP is associated with DFS. The risk of recurrence decreases with increasing survivorship, mainly in patients with adverse pathologic factors. CS can provide relevant information for clinicians and patients giving an update of their risk of subsequent recurrence.