Radiation-induced esophagitis in patients with breast cancer receiving supraclavicular nodal irradiation: A retrospective observational study

Background: Radiotherapy is an important treatment modality for locally advanced breast cancer and includes irradiation of the chest wall and supraclavicular nodes, with or without the axilla. Since the esophagus is close to the supraclavicular nodes, patients may experience acute radiation esophagitis during treatment which decreases their quality of life. Objective: To identify the dosimetric parameters of the esophagus which may affect the occurrence of esophagitis in patients with breast cancer who received supraclavicular nodal irradiation. Materials and Methods: This was a single-center retrospective observational study carried out from January 2021 to June 2022 at Father Muller Medical College Hospital, Mangalore, India. We enrolled patients with histologically proven breast cancer, who had received post-mastectomy radiation to the chest wall and supraclavicular nodes to a dose of 50 Gy in 25 fractions, 2 Gy per fraction, 5 fractions per week with 6 MV photon linear accelerator by intensity modulated radiation therapy. Toxicities were recorded every week. The parameters documented included the mean esophageal dose, maximum dose to the esophagus, and length of the esophagus within the treatment area. Results: We enrolled 25 patients with infiltrating ductal carcinoma of the breast who had undergone mastectomy and received neoadjuvant or adjuvant chemotherapy. The median age was 53 years (IQR, 44.5-63.5). Esophagitis (any grade) was noted in 18 of the 25 patients (72%). Grade 2 esophagitis developed in all 6 patients (100%) who had received a mean esophageal dose >20 Gy, and in none of the 19 (0%) who received a dose <20 Gy; P < 0.001. The development of esophagitis was not significantly associated with the esophageal length included in the treating area (P = 0.62), the maximum dose to the esophagus (P = 0.09), V10 (P = 0.49), or V20 (P = 1). The esophageal mean dose (Dmean) was the sole predictive factor for the development of esophagitis; P = 0.04. Conclusion: In patients with breast cancer receiving post-mastectomy radiation to the chest wall and supraclavicular area, the mean esophageal radiation dose is the only factor that correlates with the development of esophageal toxicity. Thus, esophageal toxicity can be reduced by prescribing dose constraints to the esophagus, thereby potentially improving the quality of life of patients.