A PROSPECTIVE, MULTICENTER EVALUATION OF PREDICTIVE FACTORS FOR POSITIVE SURGICAL MARGINS AFTER NEPHRON SPARING SURGERY FOR RENAL CELL CARCINOMA: THE RECORD1 ITALIAN PROJECT.

Aim of the study Nephron-sparing surgery (NSS) has become the standard of care for the conservative management of clinically localized renal cell carcinoma (RCC) whenever technically feasible. The excision of the tumor with a minimal margin of healthy parenchyma surrounding the neoplasm is currently considered the standard technique for NSS, in order to minimize the risk of positive surgical margins (PSMs) and achieve optimal local cancer control. We aimed to evaluate the predictors of PSMs after NSS for RCC in one of the largest available prospective multi-institutional study. Materials and methods The Italian Registry of Conservative Renal Surgery (RECORd Project) includes all patients who underwent conservative surgical treatment for radiologically diagnosed kidney cancers between January 2009 and December 2012 at 19 urological Italian centers. All preoperative anthropometric characteristics, intraoperative and pathological data were collected. Postoperative complications (within 30 days from surgery) were recorded. Standard partial nephrectomy (PN) has been defined as the excision of the tumor comprising a minimal margin of healthy peritumoral renal parenchyma. Simple tumor enucleation (SE) has been defined as the blunt tumor excision without removing a visible rim of parenchymal tissue around the pseudocapsule. Multivariable logistic regression models considering factors that were significantly related to SM status at univariable analysis were applied to analyse predictors of PSM. Results Eight hundred consecutive patients were evaluated. 761 (95.1%) and 39 patients (4.9%) achieved negative and positive surgical margins, respectively. Patients with PSMs were significantly older compared to those with negative margins (median age: 66.6 vs. 61.8 years, respectively, p=0.001). No statistically significant differences were found among patients with positive and negative margins in terms of gender, BMI, indication to NSS (elective/relative vs. imperative), symptoms at the time of diagnosis, ECOG performance status, number of lesions, clinical stage and tumor side. A higher incidence of PSMs was observed when NSS was performed for renal masses located in the upper pole (p=0.001). A lower rate of PSM was found in those patients treated with simple enucleation rather than standard partial nephrectomy (1.6% vs. 7.4% respectively,) Conclusions The early oncological goal of PN is to achieve negative margins. In our multi-institutional report of open and minimally invasive NSS, the overall rate of PSM is 4.9%. Young age, SE, middle or lower tumor location and low grade tumor are all independent predictors of NSMs.