Variation in receipt of therapy and survival with provider volume for medical oncology in non-curative esophago-gastric cancer: a population-based analysis.

BACKGROUND: While surgical care by high-volume providers for esophago-gastric cancer (EGC) yields better outcomes, volume-outcome relationships are unknown for systemic therapy. We examined receipt of therapy and outcomes in the non-curative management of EGC based on medical oncology provider volume. METHODS: We conducted a population based retrospective cohort study of non-curative EGC over 2005-2017 by linking administrative healthcare datasets. The volume of new EGC consultations per medical oncology provider per year was calculated and divided into quintiles. High-volume (HV) medical oncologists were defined as the 4-5th quintiles. Outcomes were receipt of chemotherapy and overall survival (OS). Multivariate logistic and Cox-proportional hazards regressions examined the association between management by HV medical oncologist, receipt of systemic therapy, and OS. RESULTS: 7011 EGC patients with non-curative management consulted with medical oncology. 1-year OS was superior for HV medical oncologists (> 11 patients/year), with 28.4% (95% CI 26.7-30.2%) compared to 25.1% (95% CI 23.8-26.3%) for low volume (p < 0.001). After adjusting for age, sex, comorbidity burden, rurality, income quintile, and diagnosis year, HV medical oncologist was independently associated with higher odds of receiving chemotherapy (OR 1.13, 95% CI 1.01-1.26), and independently associated with superior OS (HR 0.89, 95% CI 0.84-0.93). CONCLUSIONS: Medical oncology provider volume was associated with variation in non-curative management and outcomes of EGC. Care by an HV medical oncologist was independently associated with higher odds of receiving chemotherapy and superior OS, after adjusting for case mix. This information is important to inform disease care pathways and care organization; an increase in the number of HV medical oncologists may reduce variation and improve outcomes.