Radiation therapy improves treatment outcome in patients with diffuse large B-cell lymphoma.

The effects of radiotherapy (RT) after chemotherapy in patients with diffuse large B-cell lymphoma (DLBCL) remain unclear; several trials have yielded conflicting results. This study examined the effect of RT after cyclophosphamide, doxorubicin, vincristine, and prednisone + rituximab (R-CHOP) treatment on event-free (EFS) and overall (OS) survival. Data from 216 patients with DLBCL who were enrolled in two clinical trials at Italian Lymphoma Study Group sites and were subjected to six R-CHOP cycles and involved-field radiotherapy (IFRT) were retrospectively analyzed. IFRT treatment yielded significant EFS benefit, with a 66% reduction in the risk of death and/or disease progression. Cox analysis, when adjusted for age, gender, stage, performance status (PS), lactate dehydrogenase (LDH), and disease bulk, confirmed the significant EFS benefit of IFRT. The role of RT in DLBCL in the rituximab era is unclear. Future studies must take into account new radiation techniques and the response to chemotherapy based on functional imaging. Prospective randomized trials incorporating response-adapted therapy and modern radiation techniques are needed.