Presentation Authors: Elio Mazzone*, Giorgio Gandaglia, Milan, Italy, Sophie Knipper, Markus Graefen, Hamburg, Germany, Andrea Gallina, Milan, Italy, Derya Tilki, Hamburg, Germany, Nazareno Suardi, Marco Bandini, Vito Cucchiara, Armando Stabile, Paolo Dell'Oglio, Nicola Fossati, Francesco Montorsi, Alberto Briganti, Milan, Italy
Introduction: The occurrence of early biochemical recurrence (BCR) after radical prostatectomy (RP) represents a negative prognostic factor for clinical recurrence (CR) and mortality but its definition is unclear. We hypothesized that the definition of early BCR after RP vary according to cancer features and we aimed at developing a new individualized classification for early BCR.
Methods: Overall, 4663 PCa patients who experienced BCR after RP performed at two referral centers between 1987 and 2018 were identified. Multivariable Cox regression analyses (MVA) assessed the impact of pathologic stage, nodal status and pathologic grade group (GG) on the risk of CR after adjusting for time to BCR. MVA-derived hazard ratios (HRs) were used to identify three risk groups. A non-parametric analysis was used to explore the relationship between 8-year CR-rates and the time to BCR for each risk group. Finally, time to BCR cut-offs predicting the risk of CR were derived from the nonparametric curve for each risk group. CR-free survival was compared between patients above and below the cut-offs.
Results: Median follow-up and time to BCR were 83 and 24 months. Overall, 1,217 patients experienced CR. The 8-year CR-free survival was 74.3%. At MVA, pN1 status (HR: 2.28), GG 4-5 (HR: 2.08) and pT3b-4 stage (HR: 1.70) were associated with the risk of CR (all p < 0.001). Conversely, longer time to BCR was associated with lower risk of CR (HR: 0.98; p < 0.001). Patients were stratified in three risk groups: Low- (pN0/pNX plus pT2-3a and GG â‰¤7), Intermediate- (pN0/pNX plus pT3b-4 or GG 4-5) and High-risk (pN1). At non-parametric analysis, a non-linear increase in 8-year CR rate was observed at 12 months in low risk group and at 30 months in intermediate risk group. After stratification according to these cut-offs, 8-year CR-free survival rates were 74.9 vs. 91.9% in low risk patients who experienced BCR before and after 12 months (p < 0.001) and 57.1 vs. 87.1% in intermediate risk patients who experienced BCR before and after 30 months (p < 0.001). Conversely, in pN1 patients the risk of CR increased continuously according to the time to BCR after surgery without a non-linear cut-off. The overall 8-year CR-free survival rate in this group was 44.6%.
Conclusions: The definition of early BCR varies according to disease features. In low and intermediate risk PCa, early BCR was found to be a recurrence occurring with 12 and 30 months, respectively. Conversely, in pN1 patients a cut-off for early BCR definition could not be established.