[Correlation between pathological features at the positive margin and biochemical recurrence after radical prostatectomy in patients with organ-confined prostate cancer].

Objective： To investigate the correlation between pathological features at the positive margins and biochemical recurrence after radical prostatectomy for prostate cancer. Methods： From June 2014 to December 2019, a total of 200 patients with organ-confined prostate cancer who underwent radical prostatectomy were included in this study by the method of case matching (1∶1). One hundred patients with positive surgical margin and 100 with negative surgical margin were enrolled in this study. All patients did not receive any adjuvant treatment after surgery with a clinical stage of T2/N0. BCR-free survival was estimated using the Kaplan-Meier method. An optimal cutoff for the PSM length which differentiated risk for BCR was identified by Classification and Regression Tree analysis (CART). Cox proportional hazards regression model was used to assess the association between variables and BCR-free survival. Results： A total of 200 patients were included in this study, and 177 patients with pT2 stage were pathological after operation. The median follow-up time of this group of patients was 32.8 months ranged from 5.6 to 80.5 months. A total of 28 cases of biochemical recurrence were found through PSA follow-up after surgery, including 6 cases (6.0%) in the negative margin group and 22 cases (22.0%) in the positive margin group. The result of Kaplan Meier survival curve analysis showed that the non biochemical recurrence survival time of the negative margin group was longer than that of the positive margin group (log rank χ2=9.336, P=0.003). It was found that the length of positive margin ≥1 mm in the positive margin group was positively correlated with postoperative biochemical recurrence. Multivariate Cox proportional hazards regression was used to identify that the highest Gleason score ≥8 and the length of positive ≥1 mm were independent factors of postoperative biochemical recurrence in both the overall patients and the patients with positive margin. Conclusion：　The patients with highest Gleason score ≥8 and the length of positive ≥1mm are at elevated risk for BCR.