MP25-12 PREDICTORS OF MAJOR COMPLICATIONS AFTER CYTOREDUCTIVE NEPHRECTOMY FOR METASTATIC RENAL CELL CARCINOMA: INSIGHTS FROM A RETROSPECTIVE MULTICENTRE REGISTRY

INTRODUCTION AND OBJECTIVES: The role of cytoreductive nephrectomy (CN) in the setting of metastatic renal cell carcinoma (mRCC) is still object of great debate within the Urology community. In this regard, assessing the harms of CN is key to select patients most likely to benefit from this procedure. The aim of the study was to evaluate potential predictors of major complications (MC) after CN in a multicentre international cohort of patients with mRCC. METHODS: Data from patients with mRCC undergoing CN at 11 centers included in the REgistry of MetAstatic RCC (REMARCC) from January 2014 to December 2017 were retrospectively collected and analyzed. Patients with complete data on comorbidity profiles, intraoperative outcomes and perioperative complications formed the analytic cohort. Postoperative complications were assessed and graded using the modified Clavien-Dindo scale. MCs were defined as Clavien-Dindo grade 3 or more. Multivariable logistic regression analysiswas used to assess potential clinical predictors of 30-day readmission. RESULTS: Overall, 374 patients were included in the study. Twenty-three patients (6.1%) experienced MCs. Patient age, sex, BMI, Charlson comorbidity index, ECOG performance status, baseline Hb levels, estimated glomerular filtration rate, cT and cN status, as well as location of metastatic lesions, were comparable among patients who did and did not experience MCs. Conversely, median tumor size was significantly higher in patients experiencing MCs (11.0 vs 8.5 cm, p=0.002). Surgical approach was significantly different in the two study groups (87.0% of patients who experienced MCs were treated with open CN as compared to 65.4% of patients who did not; p=0.034). Performance of LDN was comparable among the study groups; on the contrary, removal of adjacent organs (43.5 % vs 23.4%, p=0.03), renal vein/vena cava thrombectomy (43.5% vs 17.4%, p=0.002) and metastasectomy at the time of CN (21.7% vs 7.1%, p=0.012) were significantly higher in patients who experienced MCs. Rate of hospital readmission within 30 days after surgery was significantly higher in patients who experienced MCs (11.1% vs 6.7%, p<0.0001), as well as length of hospitalization (14 vs 7 days, p=0.003). pT status was also significantly different among the study groups (p=0.014). At multivariable analysis, increasing tumor size, performance of metastasectomy at the time of CN and of renal vein/vena cava thrombectomy were found to be significantly associated with MCs in our study cohort. CONCLUSIONS: Performance of metastasectomy and need for renal vein/vena cava thrombectomy may significantly impact on the risk of major complications after CN and should be carefully considered in the preoperative surgical planning. The main study limitation is the retrospective design with risk of selection and attrition bias.