The Role of Radiotherapy After Full Course of Chemotherapy in the Treatment of Diffuse Large B-Cell Lymphoma: A Systematic Review and Meta-Analysis.

Rituximab has improved response rates and overall survival in diffuse large B-cell lymphoma (DLBCL). Radiotherapy (RT) is an effective treatment modality for lymphomas. However, significant conceptual challenges, including the application in elderly patients, varying IPI scores and CR patients, remain regarding the current use of RT. We performed a systematic review comparing chemotherapy with RT to chemotherapy alone in patients with DLBCL. We estimated hazard ratios (HR) for OS, PFS and EFS using the proportional hazards model. Five articles involving 1364 patients met inclusion criteria. Patients undergoing consolidative RT had better OS (HR = 0.46, 95% CI 0.31-0.68), PFS (HR = 0.52, 95% CI 0.22-1.25) and EFS (HR = 0.42, 95% CI 0.20-0.90) compared to those who received no RT. But no benefit was shown in patients with achievement of CR. The protective effect of consolidation RT for patients with advanced IPI scores (HR = 0.46, 95% CI 0.31-0.68) and advanced stage (HR = 0.22, 95% CI 0.08-0.59) was shown. The consolidation RT showed a significantly longer PFS (HR = 0.50, 95% CI 0.26-0.94) but no significant benefit on OS in patients with bulky disease. There was also significantly better PFS in RT patients (HR = 0.67, 95% CI 0.49-0.92), but no significant benefit on OS in old age patients. RT act as an efficacious method for DLBCL following a full course of chemotherapy. However, no OS benefit was shown in patients with advanced IPI scores, bulky disease, CR and old age.