Efficacy of Palliative Radiation Therapy (RT) for Chemotherapy Relapsed or Refractory Diffuse Large B-Cell Lymphoma: A Population-Based Retrospective Review

Lymphoma
17/11/2020

Pract Radiat Oncol. 2020 Nov 13:S1879-8500(20)30269-1. doi: 10.1016/j.prro.2020.11.003. Online ahead of print.

ABSTRACT

PURPOSE: The study objective was to investigate the effectiveness of palliative radiotherapy (RT) for diffuse large B-cell lymphoma (DLBCL) patients and to identify factors, such as chemotherapy relapsed/ refractory (R/R) disease, that may influence RT outcomes.

METHODS: Patients with DLBCL who received palliative RT from 2001-2015 in XXXXX were reviewed for patient characteristics, treatment details, and outcomes. Univariable (UVA) and multivariable analyses (MVA) for response and local progression were performed.

RESULTS: Three-hundred and seventy courses of palliative RT in 217 patients were identified. Median equivalent dose in 2Gy fractions was 19Gy (range 2-42Gy). Clinical and/or radiologic response occurred in 230 (83%) of the 276 courses with response data available. Local control following palliative RT at 6 months was 66.7%. On UVA, R/R disease was not associated with lower clinical response rates, but had higher risk of progression (hazard ratio [HR] 0.5, p=0.040). On MVA, patients with R/R disease who did not require concurrent steroids had greater response compared to those who received upfront palliative RT (odds ratio 3.5, p=0.011). Response to first-line chemotherapy and smaller lesion size were associated with improved local progression rates (HR=0.2, p=<0.001 and HR=0.5, p=0.020, respectively). RT dose fractionation factors were not significant on any analyses.

CONCLUSIONS: Palliative RT for DLBCL is effective for symptom improvement, including in the chemotherapy R/R setting. Not requiring concurrent steroids, response to first-line chemotherapy, and smaller lesion size predicted for better RT outcomes. There was no association between dose fractionation and response rates or local control to suggest that higher RT doses are more effective for palliation.