Impact of metastasectomy on cancer specific and overall survival in metastatic renal cell carcinoma: Analysis of the REMARCC registry

Introduction & Objectives: As treatment paradigms for management of metastatic renal cell carcinoma (mRCC) have shifted, the role of surgical metastasectomy in management of mRCC has been in similar flux. We examined impact on survival of surgical metastatectomy stratified in the setting of different mRCC risk groups. Materials & Methods: Multicenter retrospective analysis of patients from the REMARCC (REgistry of MetAstatic RCC) database. The cohort was subdivided utilizing Motzer RCC criteria (low, intermediate, and high risk), and impact of metastasectomy was analyzed via multivariable analysis (MVA) and Kaplan Meier analysis within each Motzer subgroup (KMA). Primary outcome was overall survival (OS) and secondary outcome was cancer specific mortality (CSM). Results: 431 patients (59 low risk, 274 intermediate risk, 98 high risk) with median follow-up of 19.2 months were analyzed. Metastasectomy was performed in 22 (37%), 66 (24%), and 32 (16%) of low, intermediate and high risk groups (p=0.012). Risk groups differed significantly with respect to ECOG performance status (p<0.001) and number of metastases at diagnosis (low 2, intermediate 3.4, high 5.1, p<0.001). MVA for CSM revealed male sex (OR 1.77, p=0.015), number of metastases at diagnosis (OR 1.18, p<0.001), and higher risk category [low (referent) vs. intermediate OR 2.16, p=0.046, high OR 2.44, p=0.002] to be independent risk factors. MVA for OS demonstrated increasing number of metastases at diagnosis (OR 1.78, p<0.001) and higher risk category [low (referent) vs. intermediate OR 2.37, p=0.03, high OR 2.61, p=0.001] to be independent risk factors. KMA for CSM demonstrated that metastasectomy was associated with longer cancer-specific survival in low (32.78 vs. 76.09 months, p=0.004) but not intermediate (p=0.060) and high risk (p=0.595) groups. KMA for OS demonstrated that metastasectomy was associated with longer median OS in the low (25.8 vs. 92.7 months, p=0.003) and intermediate risk (20.1 vs. 26.3, p=0.038), but not high risk (p=0.911) groups (Figure). Conclusions: Metastasectomy was not associated with benefit in high risk mRCC patients, but was associated with improved CSM in low risk and improved OS in low and intermediate risk mRCC patients. Further investigation is requisite to refine criteria for employment of metastasectomy.