Background: Since the 1970s, CHOP chemotherapy has been the standard treatment for patients with diffuse large B-cell lymphoma (DLBCL). In 2002, randomized trials changed this standard by showing that adding rituximab immunotherapy to CHOP improved survival. However, how these results influenced chemoimmunotherapy adoption in clinical practice remains unclear. Methods: Using the National Cancer Database to compare chemoimmunotherapy use with chemotherapy alone, we collected data on demographics, stage, health insurance, area-level socioeconomic status (SES), facility characteristics, and type of treatment for DLBCL patients diagnosed in the United States 2001-2004. Multivariable log binomial models examined associations between race, insurance, and treatment allocation, adjusting for covariates. Results: Among 38,002 patients with DLBCL, 27% received chemoimmunotherapy and 50% chemotherapy alone. Patients who had localized disease, were diagnosed in 2001 or who were black, uninsured/Medicaid insured, or lower SES were less likely to receive any form of chemotherapy (all P < 0.0001). Patients who were diagnosed in 2001 or who were black [relative risk (RR), 0.83; 95% confidence interval (CI), 0.78-0.89], >60 years (RR, 0.94; 95% CI, 0.90-0.98), or had localized disease (RR, 0.89; 95% CI, 0.86-0.92) were less likely to receive chemoimmunotherapy. Receiving treatment at high DLBCL volume teaching/research facilities was associated with the greatest likelihood of chemoimmunotherapy (RR, 1.69; 95% CI, 1.52-1.89). Conclusions: Black DLBCL patients were less likely to receive chemotherapy or chemoimmunotherapy during this period. Impact: This large national cohort study shows disparities in the diffusion of chemoimmunotherapy for DLBCL. Improving DLBCL outcomes will require efforts to extend access to proven advances in therapy to all segments of the population.
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