1063 - Dose-Volume Predictors for Radiation Esophagitis in Breast Cancer Patients Undergoing Conventional Fractionated Regional Nodal Radiotherapy: A Prospective Study
Presenter(s)
D. Q. Wang1, L. Zhao2, N. Zhang3, Y. LU4, J. Ma5, W. F. Yang6, J. Tie7, X. Hou8, X. Wang9, Y. Zhong10, X. Yu11, Q. Zhong12, H. Jing13, T. Yu1, Y. Zhai13, H. Fang13, Y. X. Li13, and S. Wang13; 1Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China, 2Department of Radiation Oncology, Xijing Hospital, Air Force Medical University, xi an, shan xi, China, 32. Department of Radiation Oncology, Cancer Hospital of China Medical University, Liaoning Cancer Hospital & Institute, Shenyang, Liaoning, China, 4Department of Radiation Oncology, Cancer Hospital of Henan Province, Zhengzhou, Henan, China, 56. Department of Radiation Oncology, Jiangsu Province Hospital of Chinese medicine, Affiliated Hospital of Nanjing University of Chinese Medicine, Nanjing, Jiangsu, China, 6Department of Radiation Oncology, Affiliated Taizhou hospital of Wenzhou Medical University, Taizhou, China, 7Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of Radiation Oncology, Peking University Cancer Hospital and Institute, Beijing, China, 8Department of Radiation Oncology, Peking Union Medical College Hospital, Chinese Academy of medical Sciences & Peking Union Medical College, Beijing, China, 9Department of Radiochemotherapy, Tangshan People's Hospital, Tangshan, China, 10Department of Radiation and Medical Oncology, Zhongnan Hospital, Wuhan University, Wuhan, China, Wuhan, China, 11Department of Radiation Oncology, Fudan University Shanghai Cancer Center, Shanghai 200032, China; Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, China; Shanghai Clinical Research Center for Radiation Oncology; Shangh, Shanghai, China, 12Department of Radiation Onoclogy, Beijing Hospital, National Center of Gerontology, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing, China, 13State Key Laboratory of Molecular Oncology and Department of Radiation Oncology, National Cancer Center/ National Clinical Research Center for Cancer/ Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
Purpose/Objective(s): Radiation esophagitis (RE) is an often overlooked in breast cancer radiotherapy. This study aimed to assess the incidence and dose-volume predictors of RE in breast cancer patients undergoing conventional fractionated regional nodal irradiation (RNI).
Materials/Methods:
Patients who met the criteria and underwent radiotherapy (RT) to the chest wall, supraclavicular/infraclavicular fossa, level II axilla, and/or internal mammary chain following mastectomy were included in the study. The prescribed dose was 50 Gy delivered in 25 fractions. The dose constraint for the esophagus was maximum dose (Dmax) <55 Gy. RE was assessed weekly during RT and at 1 and 2 weeks post-treatment, followed by follow-ups at 3 and 6 months after RT, with grading based on the Common Toxicity Criteria for Adverse Events v3.0. The esophagus was contoured from the lower edge of the cricoid cartilage to the lower margin of the aortic arch. Esophageal parameters evaluated included total volume, mean dose (Dmean), Dmax, and the relative and absolute volumes receiving at least 5-45 Gy in 5 Gy increments (RV5–RV45 and AV5–AV45). Univariate and multivariate analyses identified = grade 2 RE-related clinical and esophageal parameters. ROC curves and Youden's index determined the thresholds of = grade 2 RE-related esophageal parameters. Restricted cubic splines analyzed dose threshold trends for dose-volume predictors.Results:
In total, 581 patients were prospectively included between July 31, 2020 and February 2, 2024 (minimum post-RT follow-up: 6 months). A total of 271 (50.1%) patients had left-sided breast cancer. The prevalence of grade 2 RE was 19.8% (107/514), with no grade 3 or higher cases. The incidence of RE increased steadily during RT, with its onset at week two, reaching its peak incidence in the last week of RT and resolving after RT. All RE cases resolved within 1 month, with a median duration of 3 weeks. Univariable and multivariate analyses showed that tumor laterality (p < .001) was the risk factor for =grade 2 RE, with 26.2% for left-sided and 13.3% for right-sided tumors. Univariable analyses showed Dmean, Dmax, RV20-RV45, and AV20-AV35 were relevant dosimetric parameters of =grade 2 RE. With thresholds obtaining by ROC curves and Youden's index, relevant dosimetric parameters were converted to categorical variables for multivariate analysis with tumor laterality. Multivariate analysis showed that RV30 at a 9% threshold (11.8% vs. 26.0%, p = .032) and AV30 at a 1mL threshold (12.3% vs. 25.8%, p = .042) were dose-volume predictors for =grade 2 RE for relative and absolute volumes, respectively.Conclusion:
RE is common in breast cancer patients undergoing conventional fractionated RNI. With the same esophageal contouring standard, maintaining the upper esophageal V30 at <9% and at <1 mL may decrease the risk of RE and improve the quality of life of patients.