Vital organ sparing with proton therapy for pediatric Hodgkin lymphoma: Toxicity and outcomes in 50 patients

• Published in: Radiotherapy and oncology Vol. 168; pp. 46 - 52
• Main Authors: Tringale, Kathryn R., Modlin, Leslie A., Sine, Kevin, Forlenza, Christopher J., Cahlon, Oren, Wolden, Suzanne L.
• Format: Journal Article
• Language: English
• Published: Ireland Elsevier B.V 01.03.2022
• Subjects: Adolescent; Adult; Child; Female; Hodgkin; Hodgkin Disease - radiotherapy; Humans; Neoplasm Recurrence, Local - etiology; Organs at Risk - pathology; Proton Therapy - adverse effects; Proton Therapy - methods; Protons; Radiation; Radiotherapy Dosage; Retrospective Studies; Secondary malignancy; Toxicity; Young Adult; Protons; CTCAE; RT; HL; IMRT; PT; Toxicity; MOPP; BEACOPP; Radiation; ISRT; ILROG; ABVD; Gy; PTV; Secondary malignancy; RBE; V5Gy; V4Gy; COG; RFS; CCSS; ABVE-PC; OS; V95; V20Gy; SMR; Hodgkin; ASCT; SIR
• ISSN: 0167-8140; 1879-0887
• DOI: 10.1016/j.radonc.2022.01.016

•Pediatric Hodgkin lymphoma patients are at risk for treatment-related toxicity.•Reduced radiation dose to normal tissues can reduce morbidity and mortality.•Use of protons (PT) enabled low heart, lung, and breast dose in 50 pediatric patients.•No acute and only 1 subacute potentially PT-related grade 3–5 toxicities occurred.•Only 5 patients relapsed (all both in- and out-of-field) and all were salvaged. With high survival rates for pediatric Hodgkin lymphoma (HL), attention has turned to minimizing treatment-related morbidity and mortality. Chemotherapy and dose of radiation to organs at risk (OARs) contribute to elevated risks of secondary malignancy and cardiopulmonary disease. We sought to characterize the radiation dose to OARs, toxicities, and outcomes for pediatric HL patients treated with proton therapy (PT). Fifty patients aged 11–21 with HL consecutively treated with PT were evaluated 1–2 months following completion of PT and every 6 months thereafter. Acute and late toxicities were captured retrospectively using CTCAE v5. Patterns of relapse were characterized, and survival was assessed using Kaplan-Meier method. Most (47, 94%) patients received PT to the mediastinum. Median mean heart dose was 4.3 Gy (RBE) and median bilateral lung V20Gy was 5.8%. Median integral dose was 1.7 Gy. For the 27 female patients, a median mean dose of 0.4 and 0.3 Gy (RBE) was delivered to ipsilateral and contralateral breast tissue, respectively. No on-treatment grade 3–5 toxicities were seen. At a median follow-up of 5.3 years, no PT-related grade 3–5 toxicities or secondary malignancies developed. Five patients relapsed at a median time of 9.2 months after PT (range 2.5–24.9 months; 5-year recurrence free survival 90%). Recurrences were both in- and out-of-field in all 5 cases with no marginal failures. All relapsed patients were successfully salvaged (5-year overall survival 100%). For pediatric HL patients, proton treatment resulted in marked dose sparing of OARs with low rates of toxicity, no marginal failures, and excellent 5-year survival.