Impact of Hospital Case Volume on Outcomes Following Radical Nephrectomy and Inferior Vena Cava Thrombectomy

BACKGROUND: Radical nephrectomy with inferior vena cava thrombectomy (RN-IVCT) is a complicated procedure for which the impact of hospital case volume on overall survival (OS) is unknown. OBJECTIVE: To assess the degree to which renal cell carcinoma (RCC) with inferior vena cava tumor thrombus (IVC-TT) care is centralized and to evaluate the impact of hospital case volume on outcomes following RN-IVCT. DESIGN, SETTING, AND PARTICIPANTS: The National Cancer Data Base was queried for patients with pT3b-c RCC treated with RN-IVCT. Hospitals were classified by case volume percentile as low (<75th percentile, <0.67 cases annually), intermediate (75th-95th percentile, 0.67-2.99 cases annually), or high (>95th percentile, >3 cases annually). OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: The primary outcome was OS. Secondary outcomes were short-term (30- and 90-d) mortality rates according to hospital case volume. Kaplan-Meier curves and Cox regression model were used to evaluate OS and the effect of covariables. RESULTS AND LIMITATIONS: There were 2664 cases of RN-IVCT for pT3b-c tumors reported by 573 institutions, of which 435, 108, and 30 were classified as low, intermediate, and high volume, accounting for 28.5%, 34.5%, and 37% of cases, respectively. Treatment at high-volume institutions was associated with better OS: the median OS was 42, 53, and 60 months for low, intermediate and high-volume centers, respectively (p=0.009). After multivariable adjustment, treatment at a high-volume institution was associated with a 24% relative risk reduction for all-cause mortality compared to treatment at a low-volume institution (hazard ratio 0.76, 95% confidence interval 0.65-0.89; p=0.001). There was no significant difference in short-term mortality following RN-IVCT when stratified by hospital case volume. CONCLUSIONS: Higher hospital case volume was associated with longer OS for patients undergoing RN-IVCT. These findings support efforts to centralize care for cases of advanced RCC. PATIENT SUMMARY: In this study we looked at the impact of hospital case volume on survival following surgery for renal cell carcinoma and inferior vena cava thrombectomy. Survival was significantly better in high-volume hospitals performing three or more procedures per year.