Involved-field radiotherapy for patients with mantle cell lymphoma.

INTRODUCTION: Retrospective analysis was performed at a single institution to assess the responsiveness of mantle cell lymphoma (MCL) to involved-field radiotherapy (IFRT). METHODS: All patients treated with IFRT to at least one site of MCL between 1998 and 2012 were included. There were 25 patients who received radiotherapy to 60 disease sites. Primary endpoint was overall response rate (ORR) infield for the first site of MCL treated per patient. Predictors of ORR were analysed for the primary endpoint. Time to local progression (TLP) infield and progression-free survival were calculated from the start of the first treatment course. Analysis of all sites collectively was also undertaken. Survival analysis was conducted by the Kaplan-Meier method. RESULTS: ORR rate was 84% for the first site treated per patient. Complete response and partial response rates were 68% and 16% respectively. Median TLP following radiotherapy to the first site was not reached. Infield control rate was 91% at 12 months (95% confidence interval 69-97%). When analysis was performed on all 60 sites, ORR was 85%. Symptomatic improvement occurred after IFRT to 93% of all sites. Systemic progression outside the radiotherapy field was the predominant form of failure following IFRT. CONCLUSION: Radiotherapy generally induced a clinical response at all levels of dose administered, ranging from 3 to 36 Gy. However, increased durability of local control was suggested with higher doses. Radiotherapy is an effective treatment for palliation of MCL with objective and symptomatic responses seen over a range of radiotherapy doses.