Radiotherapy for patients with stage IV classical Hodgkin lymphoma: a propensity-matched analysis of the surveillance, epidemiology, and end results database.

Background The survival advantage of radiotherapy for patients with stage IV classic Hodgkin lymphoma (HL) has not been adequately evaluated. Methods We analyzed patients with stage IV HL enrolled from the Surveillance, Epidemiology, and End Results (SEER) registry from January 2000 to December 2012. Propensity score (PS) analysis with 1:2 matching was performed to ensure well-balanced characteristics of the comparison groups. Kaplan-Meier and Cox proportional hazardous model were used to evaluate the overall survival (OS), cancer-specific survival (CSS), the hazards ratio (HR) and corresponding 95% confidence intervals (95% CI). Results Overall, for all patients with stage IV HL, receiving radiotherapy was associated with both significantly improved OS and CSS. Radiotherapy to any lesions could independently improve the OS and CSS by 30% to 36% in the multivariate analyses before and after PS matching (PSM), with the best improvement of 33% to 40% observed for patients with nodular sclerosis (P < 0.05) among all HL pathological types. In particular, radiotherapy, most likely to the residual site, was more pronouncedly associated with the improvement in survival for patients with stage IV HL who were young (age<45, P < .05) or without B symptoms (PInteraction for OS = 0.099, PInteraction for CSS = 0.255). For those patients without B symptoms, after PSM, the OS was improved by 65% (P = .021). Conclusions The large SEER results support that radiotherapy is associated with better survival of patients with stage IV HL.