Assessment of Radiation Doses Delivered to Organs at Risk Among Patients With Early-Stage Favorable Hodgkin Lymphoma Treated With Contemporary Radiation Therapy

This case series study investigates the radiation doses delivered to organs at risk with modern involved-site radiation therapy among patients with early-stage favorable Hodgkin lymphoma treated with 20 Gy after 2 cycles of doxorubicin, bleomycin, vinblastine, and dacarbazine (ABVD). Importance Response-adapted randomized trials have used positron emission tomography-computed tomography to attempt to identify patients with early-stage favorable Hodgkin lymphoma (ESFHL) who could be treated with doxorubicin, bleomycin, vinblastine, and dacarbazine (ABVD) without radiation therapy (RT). While maximal efficacy is demonstrated with combined modality therapy, RT is often omitted in fear of late adverse effects; however, the application of modern RT could limit these toxic effects. Objective To determine the radiation doses delivered to organs at risk with modern involved-site RT among patients with ESFHL treated with 20 Gy after 2 cycles of ABVD. Design, Setting, and Participants This case series included 42 adult patients with ESFHL (according to the German Hodgkin Study Group criteria) who were treated between 2010 and 2019, achieved complete response by positron emission tomography-computed tomography (1-3 on 5-point scale) following 2 cycles of ABVD, and then received consolidative RT. The study was conducted at a single comprehensive cancer center. Exposures 2 cycles of chemotherapy followed by 20-Gy involved-site RT. Main Outcomes and Measures The medical records of patients with ESFHL were examined. Organs at risk were contoured, and doses were calculated. Progression-free survival, defined from date of diagnosis to disease progression, relapse, or death, and overall survival were estimated using the Kaplan-Meier method. Results The cohort comprised 42 patients with ESFHL (median [range] age at diagnosis, 35 [18-74] years; 18 [43%] women; 24 [57%] with stage II disease). At a median follow-up of 44.6 (95% CI, 27.6-61.6) months, the 3-year progression-free survival and overall survival rates were 91.2% (95% CI, 74.9%-97.1%) and 97.0% (95% CI, 80.4%-99.6%), respectively. The mean heart dose was less than 5 Gy (mean, 0.8 Gy; SD, 1.5 Gy; range, 0-4.8 Gy) in all patients. The mean (SD) breast dose for both breasts was 0.1 (0.2) Gy (left breast range, 0-1.0 Gy; right breast range, 0-0.9 Gy). Conclusions and Relevance In this study, combined modality therapy with 2 cycles of ABVD and 20 Gy for ESFHL was highly effective and avoided excess doses to organs at risk, which may limit long-term toxic effects. Question What are the radiation doses to normal tissues for patients with favorable Hodgkin lymphoma treated with modern involved-site radiation therapy? Findings This case series study included 42 patients with early-stage favorable Hodgkin lymphoma who were treated with combined modality therapy. The mean heart dose was less than 5 Gy in all patients, and the mean breast dose was 1 Gy or less in all 18 women. Meaning In this study, combined modality therapy for favorable Hodgkin lymphoma with contemporary radiation therapy delivered low radiation doses to organs at risk.