Main Session
Sep
27
PQA 02 - Pediatric Cancer, Sarcoma and Cutaneous Tumors, Medical Education & Professional Development, and Health Services Research
2392 - Thyroid, Cardiac and Pulmonary Function Abnormalities Following Consolidative Radiotherapy in Pediatric and Young Adult Hodgkin and Primary Mediastinal B-Cell Lymphoma Patients
Presenter(s)
Katherine Von Werne, MSN - Miami Cancer Institute: Baptist Health South Florida, Miami, FL
K. Von Werne1, M. D. Hall1,2, L. Ondrizek1, U. Abraham1, J. Juhasz1, C. H. Feng3, A. Swisher1, K. Sehrawat1, D. Daghistani4, A. Perez Perez2,5, G. Nahas2,5, M. Ramirez6, M. E. Fader7, L. Reale5, P. L. Citron5, M. P. Mehta1,2, and M. D. Chuong1,2; 1Department of Radiation Oncology, Miami Cancer Institute, Baptist Health South Florida, Miami, FL, 2Department of Oncological Sciences, Herbert Wertheim College of Medicine, Florida International University, Miami, FL, 3Memorial Health System, Hollywood, FL, 4Department of Pediatric Oncology, Miami Cancer Institute, Baptist Health South Florida, Miami, FL, 5Department of Hematologic Oncology, Miami Cancer Institute, Baptist Health South Florida, Miami, FL, 6St. Mary's Medical Center, West Palm Beach, FL, 7Nicklaus Children's Hospital, Miami, FL
Purpose/Objective(s): To report the incidence of hypothyroidism, impaired left ventricular ejection fraction (LVEF), and worsening pulmonary function tests (PFTs) following consolidative radiotherapy (RT) for lymphoma at a single institution and compare thyroid outcomes with published data using earlier RT dose paradigms and technologies. Materials/Methods: From 1/2017 to 1/2025, 51 pediatric and young adult Hodgkin lymphoma (HL) and Primary Mediastinal B-cell lymphoma (PMBCL) patients who received consolidative RT after systemic therapy were evaluated. Annual thyroid-stimulating hormone (TSH) with reflex free thyroxine (T4) levels were recommended in patients treated with neck/supraclavicular RT. LVEF was measured before RT and during follow-up with frequency specified by anthracycline exposure. PFTs were performed at baseline and 2-3 years after RT and were repeated as needed. Pre-specified treatment planning directives for organs at risk (OAR) were prospectively employed. OAR doses were extracted from RT plans. Results: Median follow-up was 4.1 years (Range: 1.0-8.8 years). Median age at RT was 17 years (Range 12-39) and included 47 HL and 4 PMBCL patients. Seven HL patients had early stage favorable, 5 early stage unfavorable, and 33 advanced stage disease; all 4 PMBCL patients were Stage IIB-X. Median dose was 30 Gy RBE (Range 20-50) delivered at 1.5-2 Gy per fraction (80.4% intensity modulated proton therapy [IMPT], 17.6% intensity modulated RT [IMRT], 2% 3D conformal RT). Mean dose to the thyroid, heart, and lungs were 10.72 Gy (Range 0-28.43), 5.7 Gy (Range 0-18.9), and 5.28 Gy (Range 0.1-15.61), respectively. The 4-year relapse-free and overall survival rates were 95.6% and 97.8%, respectively. The 4-year estimated rate of hypothyroidism was 4.1%, with two events documented in patients who received a mean thyroid dose of 21 Gy. With low event probabilities, no dosimetric factors were significantly associated with hypothyroidism. Hypothyroidism rates in this series were compared to published data identified by Pubmed search in the Table. No patients developed LVEF =50% during follow-up; one patient with LVEF 45% before RT improved to 55% after treatment. No patients developed worsening PFTs, defined as a 10% reduction in FEV1, FVC, or DLCO. One patient with restrictive lung disease before RT maintained similar PFTs at 3 years follow-up. Conclusion: In this contemporary series, early rates of hypothyroidism were low and compared favorably to historical data. Long-term surveillance is ongoing, but early results underscore the value of modern IMRT/IMPT and pre-specified OAR constraint-based planning to minimize late effects.
| Author | Journal | Year | Source | n | Technology | Mean Thyroid Dose [Standard Deviation] | New Hypothyroidism | Median F/U |
| Pinnix | IJROBP | 2018 | MDACC | 90 | IMRT | 26.2 Gy [8.24] | 66.0% | 3 years |
| Cella | IJROBP | 2012 | Naples | 61 | 3DCRT | 24.1 Gy [not reported] | 41.5% | 3.5 years |
| Present Study | - | 2026 | MCI | 51 | IMPT 80%, IMRT 18% | 10.7 Gy [8.65] | 4.1% | 4.1 years |