Positive surgical margins are predictors of local recurrence in conservative kidney surgery for pT1 tumors.

OBJECTIVES The clinical significance of positive surgical margin (PSM) after a Nephron Sparing Surgery (NSS) is controversial. The aim of this study is to evaluate the association between PSM and the risk of disease recurrence in patients with pT1 kidney tumors who underwent NSS. MATERIALS AND METHODS Retrospective cohort study. A total of 314 patients submitted to a NSS due to stage pT1 renal tumor between January 2010 and June 2015 were included. Recurrence-free survival was estimated. The Cox model was used to adjust the tumor size, histological grade, pathological stage, age, surgical margins and type of approach. RESULTS Overall PSM was 6.3% (n=22). Recurrence was evidenced in 9.1% (n=2) of patients with PSM and 3.5% (n=10) for the group of negative surgical margin (NSM). The estimated local recurrence-free survival rate at 3 years was 96.4% (95% CI 91.9 to 100) for the NSM group and 87.8% (95% CI 71.9 to 100) for PSM group (p=0.02) with no difference in metastasis-free survival. The PSM and pathological high grade (Fuhrman grade III or IV) were independent predictors of local recurrence in the multivariate analysis (HR 12.9, 95%CI 1.8-94, p=0.011 / HR 38.3, 95%CI 3.1-467, p=0.004 respectively). Fuhrman grade proved to be predictor of distant recurrence (HR 8.1, 95%CI 1.6-39.7, p=0.011). CONCLUSIONS The PSM in pT1 renal tumors showed to have higher risk of local recurrence and thus, worse oncological prognosis.