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 demonstrating that adding rituximab
immunotherapy to CHOP improved survival. However, how these results
influenced chemo-immunotherapy adoption in clinical practice remains
Using the National Cancer Database to compare chemo-immunotherapy use
with chemotherapy alone, we collected data on demographics, stage, health
insurance, area-level socio-economic 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.
Among 38,002 patients with DLBCL, 27% received
chemo-immunotherapy and 50% chemotherapy alone. Patients who had
localized disease, were diagnosed in 2001, black, uninsured/Medicaid
insured, or lower SES were less likely to receive any form of chemotherapy
(all p<0.0001). Patients who were diagnosed 2001, 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 chemo-immunotherapy. Receiving treatment at high DLBCL
volume teaching/research facilities was associated with the greatest
likelihood of chemo-immunotherapy (RR 1.69, 95% CI 1.52-1.89).
Black DLBCL patients were less likely to receive chemotherapy or
chemo-immunotherapy during this period.
This large national cohort study demonstrates disparities in the
diffusion of chemo-immunotherapy for DLBCL. Improving DLBCL outcomes will
require efforts to extend access to proven advances in therapy to all
segments of the population.