Role of radiotherapy in patients with early-stage diffuse large B-cell lymphoma of Waldeyer's ring in remission after anthracycline-containing chemotherapy.

Consolidation radiotherapy (cRT) in patients with stage I/II diffuse large B-cell lymphoma of the Waldeyer's ring (WR-DLBCL) in complete remission (CR) after induction chemotherapy (CHT) is often associated with relevant acute and chronic toxicity, and its impact on survival remains to be defined. A total of 184 patients in CR after anthracycline-based chemotherapy were retrospectively analyzed: 62 underwent CHT alone (CHT group), while 122 (66%) patients were referred to cRT (CHT + RT group). After a median follow-up of 54 months, 36 patients (20%) experienced relapse: 19% in the CHT group and 20% in the CHT + RT group. At the time of analysis 47 (76%) CHT patients and 97 (80%) CHT + RT patients were alive. Five-year overall survival (OS), disease-free survival (DFS) and lymphoma-specific survival (LSS) were 80%, 74% and 86%, respectively. Five-year OS was significantly prolonged in the CHT + RT group, while DFS and LSS were similar between groups. This discrepancy was attributed to a high percentage of deaths due to unrelated causes in CHT patients. cRT does not prolong LSS in patients with early-stage WR-DLBCL in CR after anthracycline-containing chemotherapy. An international confirmatory trial is warranted.