The role of cytoreductive nephrectomy (CN) in the immune checkpoint inhibitor (ICI) era of metastatic renal cell carcinoma (mRCC): A systematic review and individual patient data (IPD) meta-analysis of 2319 patients.

Abstract

425 Background: The combination of CN and systemic therapy has been established as one of the mainstay treatments for mRCC during the targeted therapy era. However, the role of CN in the ICI era remains unclear. Methods: We performed a systematic search of the MEDLINE, EMBASE, and Web of Science databases until August 26th, 2023, for studies comparing the combination of CN + ICI vs. ICI alone in mRCC. Using published Kaplan-Meier overall survival (OS) curves, we reconstructed IPD and then performed one-stage and two-stage meta-analyses with both parametric and non-parametric effect estimates. To account for immortal time bias, we performed 6-month and 12-month landmark analyses. We also performed a subgroup analysis according to ICI line of treatment. The risk of bias was assessed using the ROBINS-I tool. Results: We identified eight retrospective cohort studies fulfilling our inclusion criteria. Only two out of eight studies adjusted for immortal time bias and none of them adequately adjusted for all predetermined confounding factors. A total of 2319 (1264 CN + ICI and 1055 ICI only) patients were included in our analysis. Patients in CN + ICI group were younger (median age 58.2 vs. 62.8), had lower proportions of non-clear cell histology (8.8% vs. 15.2%), ≥2 metastatic sites (60.0% vs. 68.5%), liver metastases (9.0% vs. 21.9%), and poor IMDC risk score (21.7% vs. 43.9%), but had higher proportions of sarcomatoid histology (15.6% vs. 10.6%) and ≥2nd line treatment (38.1% vs. 17.1%). The combination of CN + ICI was associated with superior OS in the one stage (HR: 0.45, 95% CI 0.38–0.52), 6-month landmark (HR: 0.45, 95% CI 0.37–0.54), 12-month landmark (HR: 0.50, 95% CI 0.31–0.50) and two-stage (HR: 0.38, 95% CI 0.29–0.49) meta-analyses. Similarly, the combination of CN + ICI was associated with superior OS in the subgroup of patients receiving first-line ICI (HR 0.39, 95% CI: 0.30–0.48). Conclusions: The combination of CN + ICI for mRCC may be associated with superior OS compared to ICI alone, but currently available data are subject to selection bias. More studies, including well-designed randomized controlled trials, are needed to determine the role of CN in the ICI era. [Table: see text]