Positive surgical margins in radical prostatectomy patients do not predict long‐term oncological outcomes: results from the Shared Equal Access Regional Cancer Hospital ( SEARCH ) cohort

Objective To assess the impact of positive surgical margins ( PSM s) on long‐term outcomes after radical prostatectomy ( RP ), including metastasis, castrate‐resistant prostate cancer ( CRPC ), and prostate cancer‐specific mortality ( PCSM ). Patients and Methods Retrospective study of 4 051 men in the Shared Equal Access Regional Cancer Hospital ( SEARCH ) cohort treated by RP from 1988 to 2013. Proportional hazard models were used to estimate hazard ratios ( HR s) of PSM s in predicting biochemical recurrence (BCR), CRPC , metastases, and PCSM . To determine if PSM s were more predictive in certain patients, analyses were stratified by pathological Gleason score, stage, and preoperative prostate‐specific antigen ( PSA ) level. Results The median (interquartile range) follow‐up was 6.6 (3.2–10.6) years and 1 127 patients had >10 years of follow‐up. During this time, 302 (32%) men had BCR , 112 (3%) developed CRPC , 144 (4%) developed metastases, and 83 (2%) died from prostate cancer. There were 1 600 (40%) men with PSM s. In unadjusted models, PSM s were significantly associated with all adverse outcomes: BCR , CRPC , metastases and PCSM (all P  ≤ 0.001). After adjusting for demographic and pathological characteristics, PSM s were associated with increased risk of only BCR ( HR 1.98, P  < 0.001), and not CRPC , metastases, or PCSM ( HR ≤1.29, P  > 0.18). Similar results were seen when stratified by pathological Gleason score, stage, or PSA level, and when patients who underwent adjuvant radiotherapy were excluded. Conclusions PSM s after RP are not an independent risk factor for CRPC , metastasis, or PCSM overall or within any subset. In the absence of other high‐risk features, PSM s alone may not be an indication for adjuvant radiotherapy.