Radiotherapy of relapse-refractory follicular lymphoma

Purpose

To assess the efficacy of treatment and outcomes of patients with relapsed or refractory follicular lymphoma treated with external beam irradiation.

Patients and methods

Fifteen patients who received external beam radiotherapy for relapsed or refractory follicular lymphoma were studied. The median age was 68.3 years (range: 37.9–87.08 years) with four men and 11 women. Seven patients had early stage (I or II); eight advanced stage (III or IV). Median FLIPI score was 2. Two patients had high tumour bulk disease. Six patients had extranodal invasion, with five patients having bone marrow invasion.

Results

The median time of follow-up after relapse or first-line treatment in case of refractory disease was 61.9 months (range: 9.1–119.7 months). Complete response after external beam radiotherapy was seen in 11 cases (73%) and partial response in two (13%), with a median dose of 30 Gy (range: 2–40 Gy) and median number of fractions of 15 (range: 2–20). Eight patients (53%) relapsed after external beam radiation therapy in a median of 20.2 months, mostly out of irradiated volumes. Most patients (66%) had a disease control after one or two courses of external beam radiation therapy. At last follow-up, 86% of patients were in remission including those with salvage chemotherapy. The toxicity profile was favourable with toxicity higher than grade 1. In univariate analysis, a Follicular Lymphoma International Prognostic Index (FLIPI) score above 2 was the only predicting factor for non-control disease.

Conclusion

For relapsed and refractory follicular lymphoma, external beam radiotherapy should be considered as an effective modality when integrated in a multimodality approach. Randomised studies are warranted to validate this strategy.