Anticipating the Effect of Selective Referral on Overall Survival Following Cytoreductive Nephrectomy
Berg S, Cole A, Pucheril D, Fletcher S, Noldus J, Sood A, Abdollah F, Menon M, and Trinh QD. Anticipating the Effect of Selective Referral on Overall Survival Following Cytoreductive Nephrectomy. Eur Urol, Supplements 2018; 17(2):e623-e624.
Eur Urol Suppl
Introduction & Objectives: While the benefit of high volume care is well established in many complex disease processes, the data for radical nephrectomy is mixed, with some studies showing that high volume care is associated with a small decrease in inpatient mortality, but similar length of stay. Among men and women undergoing nephrectomy, those receiving cytoreductive nephrectomy (CN) for metastatic cancer constitute a unique subset. They have a more controversial indication for surgery, greater medical and surgical complexity, and shorter overall survival. Thus, they may stand to benefit more from high volume surgical care. Against this backdrop, we sought investigate the effect of hospital volume on overall survival among patients undergoing CN for metastatic renal cell carcinoma. Materials & Methods: We identified 12,670 patients who received CN for metastatic renal cell cancer (RCC) in the National Cancer Database from 1998 - 2012. Because patients receiving CN differ from those receiving radical nephrectomy for localized cancer, we ranked facilities based on annual CN volume. We compared patients who received surgery in facilities in the top v. bottom deciles for annual volume (mean of 8.27 CN/year v. 1.84 CN/year). Inverse probability of treatment weighting (IPTW)-adjusted Kaplan-Meier and Cox regression analyses, with hospital level clustering were used to compare overall survival between balanced cohorts of patients who underwent surgery at a high- vs. low-volume facilities. Results: Median follow-up was 60.39 months (IQR 35.12 - 95.18), median overall survival was 16 months (IQR 6.51 - 41). Following propensity score weighting, surgery at high-volume facilities was associated with a small but statistically significant decreased risk of mortality (IPTW-adjusted Cox Proportional Hazard Ratio=0.91; 95% CI: 0.87 - 0.97). On our IPTW-adjusted Kaplan-Meier analysis the median survival was 17.38 months (IQR 6.97 -43.37) at high-volume institutions vs. 15.24 months (IQR 6.18-39.1) at low-volume institutions. Conclusions: Our results suggest a small but statistically significant association between prolonged overall survival and receipt of CN at a highvolume facility. Given prospective data for CN itself suggests an overall survival benefit in the range of 3 - 10 months, our findings of a 2 month survival benefit on the basis of high volume care suggests that centralizing CN at high volume centers may be warranted.