Deferred Versus Upfront Cytoreductive Nephrectomy in MetaStatic Renal Cell Carcinoma: Comparative Survival Analysis in the Immunotherapy Era

Background: The optimal timing of cytoreductive nephrectomy (CN) in metastatic renal cell carcinoma (mRCC) remains a subject of debate, particularly in the immunotherapy era. This study compares survival outcomes between deferred CN (dCN) and upfront CN (uCN) in mRCC patients receiving modern immunotherapy regimens in the real-world setting. Methods: We retrospectively analyzed the SEER database for mRCC patients diagnosed between 2016 and 2021 who underwent dCN or uCN. The primary endpoint was overall survival (OS), while the secondary endpoints were disease-specific survival (DSS) and other-cause specific survival (OCSS). Statistical analyses included propensity score matching (PSM), Kaplan–Meier survival curves, Cox proportional hazards modeling, as well as sensitivity, subgroup, and landmark analyses. Results: A total of 1892 mRCC patients were included, with 346 patients (18.3%) undergoing dCN and 1546 patients (81.7%) receiving uCN. Patients in the uCN group were characterized with lower T stage (p < 0.001), while those in the dCN group exhibited a higher incidence of lymph node involvement (p = 0.02) and sarcomatoid dedifferentiation (p = 0.002). Following 1:2 PSM, dCN demonstrated significantly better OS and DSS, but comparable OCSS to uCN. The sensitivity and subgroup analyses suggested that dCN may substantially improve the prognosis of mRCC patients across conditions. The landmark analysis showed that the survival advantage of dCN diminished after two years of follow-up. Conclusion: dCN may be associated with improved survival outcomes compared to uCN in selected mRCC patients receiving immunotherapy, and careful patient selection for dCN or uCN is essential.