Consolidative radiation therapy may provide a significant benefit to patients with specific subtypes of diffuse large B-cell lymphoma (DLBCL), according to research presented at the American Society for Radiation Oncology (ASTRO) annual meeting (September 24-27, 2017; San Diego, CA).
Utilization of consolidative radiation therapy after standard of care rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) in early-stage DLBCL remains controversial. Recent research has shown that double-hit and triple-hit are aggressive subtypes of DLBCL, but researchers have yet to explore the efficacy of radiation therapy in these subtypes.
Matthew Mills, University of South Florida Morsani College of Medicine, and colleagues conducted a study to evaluate the outcome of patients treated with systemic therapy followed by consolidative radiation therapy for double-hit and triple-hit DLBCL. A total of 188 patients (209 lesions) with early-stage DLBCL from 1998 to 2014 were retrospectively analyzed for clinical characteristics, treatments, outcomes, and molecular profiles. Twenty-seven patients (14%) were identified as having double-hit disease, and 10 patients (5%) were identified as having triple-hit disease.
Primary outcomes included time to relapse and overall survival (OS).
Patients with double-hit and triple-hit DLBCL treated with R-CHOP benefited substantially from consolidative radiation therapy, with a 36-month time to relapse rate of 64%. Patients treated without radiation therapy had a 36-month time to relapse rate of 11%.
Multivariate analysis confirmed these results, showing that patients who received radiation therapy had almost double the rate of time to relapse at 36 months compared with those who just received systemic therapy (83% vs 46%, respectively, P < .0001).
Researchers concluded that receipt of radiation therapy, along with double-hit or triple-hit subtype of DLBCL, are factors that contribute to time to relapse. While double-hit and triple-hit status have strong correlations with worse OS in patients with DLBCL, researchers speculate that consolidative radiation therapy may offer a significant benefit to this cohort of patients. “Early identification of these patients for more aggressive treatment utilization may lead to improved outcomes,” they wrote.—Zachary Bessette