The role of radiotherapy as salvage and/or consolidation treatment in relapsed/refractory and high-risk diffuse large B-cell lymphoma

ObjectiveMany salvage therapies have been proposed for relapsed/refractory (R/R) diffuse large B-cell lymphomas or for consolidation in the case of suboptimal response. Radiotherapy (RT) is one modality of salvage therapy, but its place is currently not well defined. MethodThis study reports a retrospective review of patients receiving unplanned radiotherapy for R/R diffuse large B-cell lymphoma (DLBCL) or primary mediastinal B-cell lymphoma (PMBCL), or as consolidation therapy after second-line chemotherapy, treated in our hospital. ResultsFifty-one patients with a median age of 53.5years [19-89] were selected. The histologic type was DLBCL in 35 cases (68%), PMBCL in 8 cases (16%), and secondary transformed NHL in 8 cases (16%). Median aaIPI was 1 [0-4], and 17 patients (33%) had a high tumor burden (bulky disease). Sixteen patients (31%) were irradiated for a response considered to be insufficient, 18 patients (36%) were refractory, and 17 patients (33%) had relapsed. Patients were irradiated with a median dose of 40Gy [15-44], 29 (57%) by a conformal 3D technique and 22 (43%) by tomotherapy. With a median follow-up of 36months [1.0-127.8] after irradiation, 5-year progression-free survival (PFS) and overall survival (OS) were 62% and 72%, respectively. In multivariate analysis, adverse factors associated with PFS and OS in our cohort were age >70years (HR=5.06, P=.02) and post-RT relapse (HR=12.24, P=.002), whereas favorable factors were number of lines of chemotherapy <3 (HR=0.02, P=.03) and bulky disease (HR=0.02, P=.009). ConclusionDue to its low toxicity and ease of use, radiotherapy should therefore remain an available option in patients with R/R DLBCL or as consolidation therapy in patients with high-risk disease, mostly in patients with chemo-sensitive disease or bulky disease.