2326 - Radiation Pneumonitis after Contemporary Whole Lung Irradiation in Pediatric Sarcomas and Wilms Tumor
Presenter(s)
O. Haisraely1, M. F. F. McAleer2, S. L. McGovern3, M. Chintagumpala4, J. Foster5, S. Fetzko6, V. Smith6, G. S. Manzar7, S. Whittle6, and A. C. Paulino7; 1Tel Aviv Sourasky Medical Center (Ichilov), Tel Aviv, Israel, 2Division of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, 3Department of Radiation Oncology, Division of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, 4Texas Children's Cancer Center, Baylor College of Medicine, Houston, TX, 5Texas Children's Hospital, Houston, TX, 6Texas Children Hospital, Houston, TX, 7Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX
Purpose/Objective(s): Whole lung irradiation (WLI) is a standard treatment for pediatric patients with pulmonary metastases from Wilms tumor, Ewing sarcoma, and rhabdomyosarcoma. Modern radiation techniques such as IMRT and VMAT are increasingly used because of potential dosimetric advantages over conventional AP/PA fields. We evaluated the incidence of radiation pneumonitis (RP) and associated clinical and dosimetric factors after WLI using contemporary techniques.
Materials/Methods: We retrospectively identified pediatric patients (=21 years) treated with WLI at our center between 2010 and 2024 using IMRT, VMAT, or 3D conformal techniques. Demographic, clinical, and dosimetric variables were abstracted from medical records and treatment planning systems. RP was graded according to CTCAE version 5.0 pneumonitis. Follow-up at 6 months and 1 year was 82% and 75.6%, respectively.
Results: Seventy-eight (78) patients received WLI. Median age was 7 years (range, 1.5–19), and median prescribed dose was 12 Gy (range, 10.5–18 Gy). Histologies included Wilms tumor (52.6%), Ewing sarcoma (31.5%), rhabdomyosarcoma (14.4%), and synovial sarcoma (1.3%). WLI technique was AP/PA in 23 patients (29.5%), IMRT in 22 (28.2%), and VMAT in 33 (42.3%). Six patients (7.6%) developed RP; four (5.1%) had symptomatic grade 2 pneumonitis. The median time to pneumonitis onset was 2.5 months (range: 1.5-4 months) following completion of radiation. No grade =3 events occurred. Among patients who developed pneumonitis, 66% received a thoracic/lung boost compared to 16.6% of those who did not developed RP (?²=8.8, p=0.003). A trend toward higher V20 was observed, but this did not reach statistical significance (p=0.09). Mean lung dose and maximum lung dose were not associated with RP. RP incidence did not differ between techniques.
Conclusion: Radiation pneumonitis was infrequent and mild after pediatric WLI. Lung or chest wall boost was the only factor associated with RP, and IMRT and VMAT were not associated with increased pneumonitis compared with conventional techniques.