Oncologist volume and outcomes in older adults diagnosed with diffuse large B cell lymphoma

Abstract

Although provider-level volume is frequently associated with outcomes in cancers requiring complex surgeries, whether similar relations exist for cancers treated primarily with systemic therapy is unknown. Using a population-based cohort analysis of older adults diagnosed with diffuse large B cell lymphoma (DLBCL) during the years 2004-2011, we evaluated the association between oncologist volume and 4 clinical outcomes (receipt of any chemotherapy, receipt of an anthracycline-containing or equivalent regimen, early hospitalization, and overall survival). Our primary explanatory variable was lymphoma treatment volume, defined as the number of patients with newly diagnosed lymphoma for which an oncologist initiated therapy during a 12-month look-back period from each incident DLBCL case. We identified 8247 Medicare beneficiaries who were newly diagnosed with DLBCL. Chemotherapy was administered to 6202 (75.2%) beneficiaries, and 71.4% of cytotoxic regimens contained an anthracycline. Beneficiaries who were treated by higher-volume oncologists had increased odds of receiving chemotherapy (adjusted odds ratio [aOR], 1.45; 95% confidence interval [CI], 1.24-1.70; P <.001) and of receiving an anthracycline-containing regimen (aOR, 1.26; 95% CI, 1.06-1.50; P = .009). Receiving care from a higher-volume provider was also associated with decreased hospitalization (aOR, 0.80; 95% CI, 0.69-0.95; P = .007) and improved survival (adjusted hazard ratio, 0.85; 95% CI, 0.79-0.92; P < .001). In older adults diagnosed with DLBCL, receiving care from a provider with more experience treating lymphoma patients was associated with receipt of guideline-adherent therapy, reduced hospitalizations, and improved survival. Clinical volume may be an important factor in providing high-quality cancer care in the modern era.