Low Dose Involved Site Radiotherapy as Single Modality Treatment for Early-Stage Nodular Lymphocyte Predominant Hodgkin Lymphoma.

Abstract

Involved site radiotherapy as a single modality is considered standard of care for early-stage non-bulky nodular lymphocyte predominant Hodgkin's Lymphoma (NLPHL) with excellent rates of local control and overall survival. Guidelines suggest a dose of 30 Gy in conventional fractionation, however NLPHL has an indolent course and clinically behaves likes a low-grade lymphoma. Given the good prognosis NLPHL has been treated as low grade non-Hodgkin's lymphoma with a dose of 24 Gy in 12 fractions. Eleven patients with stage I-II non-bulky NLPHL treated with involved site radiotherapy alone to a dose of 24 Gy in 12 fractions between 2010 and 2021 were respectively identified and reviewed. Data on toxicity, post treatment PET, relapse and site of relapse were recorded from multidisciplinary meetings records and regular six monthly clinic reviews. Mean patient age was 45 (range 25-74), 9 were male. 8 were classified as having Ann-Arbor stage IA disease, and the remaining 3 had IIA disease. All patients were prescribed 24 Gy in 12 fractions, 6 patients had 3D-conformal radiotherapy, 1 static IMRT and 4 VMAT. After a median follow up of 32 months (range 12-147) the overall response rate was 100% and all patients had complete metabolic response on PET scan, performed three months following the completion of radiotherapy. All patients remained disease free throughout the follow up period (PFS and OS 100%). There were no late toxicities reported. This is the largest reported series of NLPHL patients treated with low dose involved site modern radiotherapy. Patients had excellent local control rates and survival with no significant toxicity, supporting the use of 24 Gy in early-stage non-bulky disease.