Predicting positive surgical margins in partial nephrectomy: A prospective multicentre observational study (the RECORd 2 project)

PURPOSE: to evaluate clinical predictors of positive surgical margins (PSMs) in a large multicenter prospective observational study and to develop a clinic nomogram to predict the likelihood of PSMs after partial nephrectomy (PN). MATERIALS AND METHODS: We prospectively evaluated 4308 patients who had surgical treatment for renal tumors between January 2013 and December 2016 at 26 urological Italian Centers (RECORd 2 project). Two multivariable logistic models were evaluated to predict the likelihood of PSMs. Center caseload was dichotomized using a visual assessment adjusted for several predictors of PSMs. A nomogram predicting PSMs was developed. RESULTS: Overall, 2076 patients treated with PN were evaluated. pT1a, pT1b, pT2 and pT3a were recorded in 68.7%, 22.6%, 2.1% and 6.6% of the patients, respectively. PSMs were recorded in 342 (16.5%) patients. From a null multivariable model against number of PN/year, 60 PN/year were identified as the best cut-off to define a high-volume centre. At multivariable analysis, clinical stage (cT1a vs. cT2 [OR 1.94]; p = 0.03), volume centre (≤60 PN/year) (OR 2.22; p