Impact of hospital nephrectomy volume on intermediate- to long-term survival in renal cell carcinoma.

ABSTRACT

OBJECTIVE: To evaluate the relationship between hospital volume and intermediate- and long-term patient survival for patients undergoing nephrectomy for renal cell carcinoma (RCC). PATIENTS AND METHODS: Adult patients with RCC treated with nephrectomy between 2000 and 2010 were identified from the English Hospital Episode Statistics database and National Cancer Data Repository. Patients with nodal or metastatic disease were excluded. Hospitals were categorised into low- (LV; <20 cases/year), medium- (20-39 cases/year) and high-volume (HV; ≥40 cases/year), based on annual cases of RCC nephrectomy. Multivariable Cox regression analyses were used to calculate hazard ratios (HRs) for all-cause mortality by hospital volume, adjusting for patient, tumour and surgical characteristics. We assessed conditional survival over three follow-up periods short (30 days to 1 year), intermediate (1-3 years) and long (3-5 years). We additionally explored whether associations between volume and outcomes varied by tumour stage. RESULTS: A total of 12 912 patients were included. Patients in HV hospitals had a 34% reduction in mortality risks up to 1 year compared to those in LV hospitals (HR 0.66, 95% confidence interval 0.53-0.83; P < 0.01). Assuming causality, treatment in HV hospitals was associated with one fewer death in every 71 patients treated. Benefit of nephrectomy centralisation did not change with higher T stage (P = 0.17). No significant association between hospital volume and survival was observed beyond the first year. CONCLUSIONS: Nephrectomy for RCC in HV hospitals was associated with improved survival for up to 1 year after treatment. Our results contribute new insights regarding the value of nephrectomy centralisation.