Sep 28

PQA 02 - Lung Cancer/Thoracic Malignancies, Patient Reported Outcomes/QoL/Survivorship, Pediatric Cancer

2380 - Intentional Protection of the Contralateral Esophagus in Thoracic Radiotherapy for Lung Cancer

04:45pm - 06:00pm PT

Hall F

Screen: 23

Presenter(s)

Jia-Qi Huang, - Department of Radiation Oncology, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, Shanghai

J. Q. Huang^1,2, S. Li^1,2, H. Li¹, J. Y. Chen^1,2, W. X. Qi¹, and S. Zhao¹; ¹Department of Radiation Oncology, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China, ²Shanghai Key Laboratory of Proton Therapy, Shanghai, China

Purpose/Objective(s): The incidence of acute radiation-induced esophagitis (ARIE) in lung cancer patients undergoing thoracic radiation therapy (RT) is 15% to 25%, leading to a significant decline in quality of life and potentially compromising treatment outcomes. The hypothesis is that a mean dose constraint to the contralateral esophagus reduces the incidence of acute radiation-induced esophagitis. This study aims to evaluate the feasibility and efficacy of a contralateral esophagus-sparing technique in reducing the incidence of ARIE.

Materials/Methods: A total of 84 patients with lung cancer who underwent thoracic RT between May 2023 and January 2025 were analyzed. Injury-effective esophagus (IEE) was defined as the esophageal region located within 5 mm of the clinical target volume (CTV) and extending 2 cm both cranially and caudally along the planning target volume (PTV). The esophageal region located within the IEE and outside the PTV was delineated as the esophagus-sparing (ES) area. The total overlap volume between PTV and IEE within the same transverse plane was quantified into three categories (<1/3, 1/3-2/3, >2/3). Accordingly, the mean dose (Dmean) to the ES area for these categories was constrained to 1/3, 1/2, and 2/3 of the prescribed dose, respectively. Dose-volume parameters were collected and evaluated. ARIE was accessed according to the RTOG acute toxicity grading system.

Results: Thirty five patients (41.7%) with non-small cell lung cancer and forty nine patients (58.3%) with small cell lung cancer were included in this study. The median age at the initiation of RT treatment was 68 years (range 48-80). The cumulative incidence of ARIE was 28.6% during the median follow-up of 444 days (95%CI 376-480). Grade 1 or 2 ARIE occurred in 15 patients (17.9%) and 8 patients (9.5%), respectively. The incidence of grade 3 ARIE was limited to one patient at the end of treatment, who achieved recovery following a week-long hospitalization. No instances of grade 4 or 5 ARIE or late esophageal injury were observed. Multivariate Cox regression analysis identified palliative radiotherapy (HR 3.6, 95% CI 1.53-8.5, P=0.003) and esophagus V40_Gy=16.3% (HR 3.4, 95% CI 1.36-8.4, P=0.009) as independent risk factors for ARIE after applying contralateral esophagus-sparing technique. Eleven patients (13.1%) failed to meet the Dmean constraint due to the impact of individual PTV shapes on target coverage.

Conclusion: The method of effectively constraining the mean dose to the contralateral esophagus is technically feasible and can significantly reduce the incidence of ARIE. Prospective studies are warranted to confirm these findings.