Reexamining the Association Between Positive Surgical Margins and Survival After Partial Nephrectomy in a Large American Cohort

Purpose: To investigate the impact of positive surgical margins (PSM) on overall survival (OS) in a large American cohort with intermediate-term follow-up. Patients and Methods: Using the National Cancer Data Base, we identified 6038 cases of pathological T1-T3a, nonmetastatic renal-cell carcinoma managed with partial nephrectomy (PN) from 2003 to 2006. Patients were stratified into two groups based on margin status. Predictors of positive margins were evaluated using multivariable logistic regression analysis. OS by margin status was evaluated using Kaplan-Meier analysis and the log-rank test. A multivariable Cox proportional hazards model was used to evaluate the adjusted association between margin status and survival. Results: Overall, 302 (5.3%) patients had positive margins. On multivariable analysis, higher pathological T stage and higher comorbidity score were the only factors significantly associated with positive margins (p < 0.001 and p = 0.015, respectively). At 71-month median follow-up, the unadjusted 5-year OS for the entire cohort was 92%. Positive margins were significantly associated with decreased 5-year OS (89% vs 92%, p = 0.002), and this association remained significant in healthy patients (p = 0.027). On multivariable survival analysis, positive margins significantly predicted hastened time to all-cause death (hazards ratio 1.34; 95% CI 1.01, 1.78; p = 0.038). Conclusion: In the largest observational study to date, PSM were associated with worse OS after PN. Further study on cancer-specific outcomes with long-term follow-up is needed.