Effects of Chemoradiotherapy Versus Chemotherapy Alone on Survival of Patients with Primary Mediastinal Large B-cell Lymphoma

Objective To explore the prognostic factors of primary mediastinal large B-cell lymphoma (PMBCL) and the effects of chemoradiotherapy versus chemotherapy alone on patients' prognosis before and after rituximab era. Methods We extracted the data of PMBCL patients diagnosed from 2001 to 2015 from SEER database. SEER Stat software was used to calculate the incidence rate. Kaplan-Meier method and Cox regression model were used to analyze the impact of various clinical variables on prognosis. Results We included 635 patients with PMBCL. Multivariate Cox regression analysis showed that age, stage and chemotherapy were independent prognostic factors. Kaplan-Meier survival analysis showed that OS of the patients receiving chemotherapy only in 2006-2015 was significantly better than that in 2001-2005 (χ2=10.002, P=0.002). The patients who received chemoradiotherapy had better OS than those who received chemotherapy alone from 2001 to 2005. The OS and DSS of patients receiving chemoradiotherapy were not significantly different from those of chemotherapy alone from 2006 to 2015. Conclusion The application of rituximab improves the long-term survival of PMBCL patients. The prognosis of patients who received chemoradiotherapy is comparable to that of chemotherapy alone from 2006 to 2015.