Comparison of Esophageal Dose Parameters in Breast Cancer Radiotherapy With and Without Esophageal Contouring

Context This study investigates the effect of esophageal delineation on dose-volume parameters during breast cancer radiotherapy (RT), aiming to optimize treatment planning and reduce the risk of acute esophageal toxicity. Methods A retrospective study was conducted on radiotherapy plans from 100 patients with breast cancer (mean age: 45 years) who received three-dimensional conformal radiotherapy (3DCRT) targeting the chest wall and supraclavicular fossa (SCF). All patients were treated with a hypofractionated schedule of 40 Gy in 15 fractions. Initially, esophageal contouring was excluded. In a secondary phase, the esophagus was delineated as an organ at risk (OAR), and the plans were revised accordingly. Dosimetric comparisons included maximum (D_max), minimum (D_min), and mean (D_mean) esophageal doses, along with the volume of the esophagus receiving doses ≥5 Gy (V5), ≥10 Gy (V10), ≥15 Gy (V15), ≥20 Gy (V20), ≥25 Gy (V25), and ≥33 Gy (V33). Additionally, ipsilateral lung volumes (V4, V8, and V16), the Homogeneity Index (HI), and Conformity Index (CI) were assessed to evaluate plan quality. Results Delineating the esophagus significantly reduced the radiation dose it received (p < 0.05), without affecting planning target volume (PTV) coverage or compromising plan quality, as indicated by consistent HI and CI values; lung dose parameters remained largely unchanged, although higher mean esophageal doses were observed in left-sided breast cancer cases due to the esophagus's closer proximity to the supraclavicular fossa, which made beam modulation more challenging. Conclusions Incorporating esophageal delineation in 3DCRT planning for breast cancer significantly reduces esophageal dose exposure without compromising dosimetric quality. This adjustment may contribute to minimizing acute esophageal toxicity and enhancing treatment safety.