Salvage radiotherapy in patients with recurrent or refractory primary or secondary central nervous system lymphoma after methotrexate-based chemotherapy

BackgroundTo assess the efficacy of salvage radiation therapy (RT) in patients with recurrent/refractory primary or secondary central nervous system lymphoma (CNSL) after initial methotrexate (MTX)-based chemotherapy and to identify factors associated with treatment outcome.Patients and methodsWe reviewed 36 patients with primary or secondary CNSL who relapsed after MTX therapy and received salvage RT. Primary end points were radiographic response and overall survival (OS).ResultsAfter salvage RT, 18 patients (50%) achieved a complete radiographic response and 6 (17%) achieved a partial response, for an overall response rate of 67% 95% confidence interval (CI) 49% to 81%]. The median OS from start of salvage RT was 11.7 months (range: 0.6–94.7). Patients treated with less than five cycles of MTX before failure had a significantly shorter OS than patients who received five or more cycles (9.2 months versus not reached, P = 0.04). Patients with CNSL limited to brain only had a significantly longer OS than patients with disease in the brain and other central nervous system locations (16.5 versus 4.5 months, P = 0.01).ConclusionSalvage RT is effective for patients with recurrent/refractory primary or secondary CNSL after initial MTX therapy. Having received five or more cycles of MTX before failure and CNSL limited to the brain at relapse are associated with longer OS.