Who undergoes cytoreductive nephrectomy now? An analysis of perioperative risk characteristics in contemporary patients.

493 Background: Cytoreductive nephrectomy (CN) has traditionally been the first step in managing metastatic renal cell carcinoma (mRCC). However, the role of routine upfront cytoreductive nephrectomy in mRCC was questioned by the 2018 publications of CARMENA and SURTIME. That same year, Checkmate 214 highlighted the superior effectiveness of immune checkpoint inhibition as first-line systemic therapy in mRCC compared to sunitinib. IMDC risk assessment is widely used in mRCC decision-making. Data from the ACS-NSQIP, a validated method for assessing surgical risk, is commonly used to predict perioperative mortality and morbidity. We sought to understand how the risk characteristics of patients undergoing CN have changed since the reporting of CARMENA, SURTIME, and Checkmate 214 in 2018. Methods: This study used ACS-NSQIP data sets from 2015-2022. It included patients undergoing nephrectomy for mRCC with disseminated cancer, excluding those from 2018. Baseline characteristics and perioperative outcomes were compared using chi-square tests, t-tests, or logistic regression as appropriate. Data was available to approximate 3 of the 6 IMDC criteria (anemia, thrombocytosis, and performance status). Results: Of 82268 nephrectomies performed from 2015-2022, 2191 CN were appropriate for inclusion. The proportion of CN as a share of all nephrectomies in NSQIP has decreased since 2018 (Table, p<0.05). Similarly, the proportion of patients undergoing CN with at least 1, 2, or 3 IMDC criteria has also dropped (Table, p<0.05). The median NSQIP-predicted mortality and morbidity have significantly declined (Table, p<0.05). Assessment of 18 baseline characteristics revealed that no single factor could fully account for the observed risk differences. Since 2018, the median length of stay has reduced from 4 to 3 days, and the proportion of outpatient surgeries has risen from 2.6% to 6% (p<0.05). Despite variations in baseline risk, no significant differences were observed in mortality, major complications, operative characteristics, or readmission rates. Conclusions: Since 2018, patients undergoing CN have had lower IMDC and NSQIP risk profiles, and the overall number of CN procedures has declined. These shifts should be taken into account when interpreting historical data on CN. Further research is needed to assess whether this more selective approach to CN has resulted in improved outcomes since 2018. Characteristics of patients undergoing CN (all p<0.05). Characteristic Pre-2018 (n=1165) Post-2018 (n=1026) Cytoreductive nephrectomy / total nephrectomies in NSQIP during period 1165/32071 = 3.6% 1026/50197 = 2.0% Minimum IMDC Criteria* 0 50.0% 54.5% 1 39.1% 37.7% 2 10.2% 7.8% 3 0.7% 0% Predicted Mortality Median 1.5% 1.2% 90 th percentile 5.6% 4.8% Predicted Morbidity Median 10.3% 9.9% 90 th percentile 14.0% 12.3% *Only anemia, thrombocytosis, and performance status could be assessed.