Long-Term Survival Outcomes of Cytoreductive Nephrectomy Combined with Targeted Therapy for Metastatic Renal Cell Carcinoma: A Systematic Review and Individual Patient Data Meta-Analysis

SIMPLE SUMMARY: Cytoreductive nephrectomy (CN) refers to the removal of the primary renal tumor in the setting of metastatic renal cell carcinoma. In the past, the combination of CN with cytokine-based immunotherapy was considered the standard of care. However, CN’s role during the targeted treatment era remains controversial. We attempted to address this issue by performing a systematic review and meta-analysis of the literature. We synthesized data from 15 studies comparing CN and targeted therapy to targeted therapy alone. Our results show that CN combined with targeted therapy was associated with increased survival compared to targeted therapy only. Careful patient selection is required to take full advantage of any survival benefit that CN may offer. Future research endeavors should focus on developing appropriate prognostic models to guide appropriate patient selection for CN. ABSTRACT: The role of cytoreductive nephrectomy (CN) in the treatment of metastatic renal cell carcinoma (mRCC) remains controversial during the targeted therapy era. To reconcile the current literature, we analyzed the reported survival data at the individual patient level and compared the long-term survival outcomes of CN combined with targeted therapy vs. targeted therapy alone in patients with mRCC. We performed a systematic review of the literature using the MEDLINE, Scopus, and Cochrane Library databases (end-of-search date: 21 July 2020). We recuperated individual patient data from the Kaplan–Meier curves for overall (OS), progression-free (PFS), and cancer-specific survival (CSS) from each study. We subsequently performed one-stage frequentist and Bayesian random-effects meta-analyses using both Cox proportional hazards and restricted mean survival time (RMST) models. Two-stage random-effects meta-analyses were also performed as sensitivity analyses. A subgroup analysis was also performed to determine the effect of CN timing. Fifteen studies fulfilling our inclusion criteria were identified, including fourteen retrospective cohort studies and one randomized controlled trial. In the one-stage frequentist meta-analysis, the CN group had superior OS (hazard ratio [HR]: 0.58, 95% confidence interval [CI]: 0.54–0.62, p < 0.0001) and CSS (HR: 0.63, 95% CI: 0.53–0.75, p < 0.0001). No meaningful clinical difference was observed in PFS (HR: 0.90, 95% CI: 0.80–1.02, p = 0.09). One-stage Bayesian meta-analysis also revealed superior OS (HR: 0.59, 95% credibility interval [CrI]: 0.55–0.63) and CSS (HR: 0.63, 95% CrI: 0.53–0.75) in the CN group, while no meaningful clinical difference was detected in PFS (HR: 0.91, 95% CrI: 0.80–1.02). Similar results were obtained with the RMST models. The OS benefit was also noted in the two-stage meta-analyses models, and in the subgroup of patients who received upfront CN. The combination of CN and targeted therapy for mRCC may lead to superior long-term survival outcomes compared to targeted therapy alone. Careful patient selection based on prognostic factors is required to optimize outcomes.