Role of radiation therapy in primary central nervous system lymphoma : KROG 14-20 Collaborative Study of Brain and Lymphoma Committee.

We analyzed patterns of care and outcomes for patients with primary central nervous system lymphoma (PCNSL) in this multi-institutional retrospective study. Between January 2000 and December 2011, 220 patients with PCNSL received radiotherapy (RT). Among these patients, 26 patients received RT alone; 179 patients were treated with chemotherapy and radiotherapy; the rest of the patients (N = 15) initially underwent chemotherapy alone, then received RT as a salvage treatment. Most of the patients (N = 188) received methotrexate-based chemotherapy. The median follow up duration was 38 months (range 3-179 months). The median RT dose and whole brain RT (WBRT) dose were 45.0 Gy (range 20.0-59.4) and 30.6 Gy (range 18.0-45.0), respectively. Seventy-seven (35%) patients received WBRT alone, and 143 patients (65%) underwent WBRT plus boost RT. Total RT dose and WBRT dose decreased during the study period. The median survival was 64 months and actuarial 5-year overall survival was 51.4%. In multivariate analysis, age (P < 0.001), ECOG performance status (P = 0.036), deep structure involvement (P = 0.011) and treatment response (P = 0.001) were significant prognosticators. RT combined with chemotherapy is effective modality for treatment of PCNSL. The survival outcome improved in spite of total radiation dose and whole brain RT (WBRT) dose having been decreased over the study period, indicating that low-dose WBRT could be effective.