Treatment facility volume and survival in patients with metastatic renal cell carcinoma.

Abstract

594 Background: Higher treatment facility (TF) volume has been linked with improved surgical and hematologic malignancy outcomes. We evaluated the association between TF volume and overall survival (OS) in pts with metastatic renal cell carcinoma (mRCC). Methods: The National Cancer Data Base was queried for all pts with mRCC and survival data available (2004 to 2013, cohort A). We defined high volume TFs as those in the top 20th percentile of mean number of mRCC pts treated per year ( > 5 pts). The effect of volume on OS was determined using unadjusted Kaplan-Meier curves and Cox regression models (MVA) adjusting for pt (age, sex, race, ethnicity, insurance type, income, Charlson-Deyo Score), facility (location, practice setting) and clinical characteristics (histology, presence or absence of liver and lung metastasis). Increasingly more stringent inclusion criteria were used to confirm the overall cohort association (cohort B = mRCC pts with active treatment; cohort C = mRCC pts with systemic therapy; cohort D = mRCC pts with systemic therapy at the reporting institution; cohort E = mRCC pts with systemic therapy at the reporting institution with liver and lung metastatic status known). Results: There were 44,109 mRCC pts treated at 1,224 TFs. The median age was 65, 66% were men and 75% had clear cell mRCC. Median TF volume was 2.4 pts/year (range 0.1-46.8). High volume TFs treated 54% of all mRCC pts. The unadjusted median overall survival of mRCC patients (cohort A) treated at high vs low volume TFs was 9.2 vs 6.4 months (P < 0.0001). This difference was maintained in all cohorts: cohort B = 13.7 vs 10.9, cohort C = 12.4 vs 10.0, cohort D = 12.5 vs 9.3, and cohort E = 13.4 vs 10.6 months (P < 0.0001 for all cohorts). MVA confirmed that facility volume was associated with all-cause mortality after adjustment: HR = 0.85, [95% CI 0.82-0.88], P < 0.001. These results were consistent regardless of inclusion criteria, e.g. for cohort E: HR = 0.839, [95% CI 0.785-0.897], P < 0.0001. Considering the definition of high volume, all thresholds > 5 pts/year showed a survival benefit, with the largest effects at ≥10 pts/year. Conclusions: Patients with mRCC treated at higher volume facilities had a longer survival compared with those treated at lower volume facilities.