Comparison of dose volumetric parameters of oesophagus in the radiation treatment of carcinoma breast with and without oesophagus delineation

Abstract

Aim: There are only limited studies available in literature that discuss methods to reduce the oesophageal dose and acute oesophagitis during breast cancer radiotherapy. The aim of this study is to compare dose volumetric parameters of oesophagus in radiation treatment of breast with and without oesophagus delineation. Methods: Treatment plans of 44 patients, who underwent chest wall and supraclavicular fossa irradiation, were selected for the study. Oesophagus was later delineated and treatment replanned using three-dimensional conformal radiotherapy (3DCRT) considering oesophagus as an organ at risk (OAR). The dose prescribed was 40 Gy/15 fractions to the planning target volume (PTV). Dose volumetric parameters of oesophagus such as maximum dose (Dmax), mean dose (Dmean), the percentage of oesophagus volume receiving ≥15Gy (V15), ≥25Gy(V25), ≥33Gy(V33) and ipsilateral lung volume parameters V4, V8 and V16 were compared with already executed plans in which oesophagus was not delineated. Results: Contouring the oesophagus as an OAR as a part of the radiotherapy treatment for Carcinoma Breast resulted in statistically significant reduction in dose to the oesophagus. No statistically significant change was found in the ipsilateral lung volume parameters. No compromise in plan quality was required as evident from the statistically non-significant differences in Homogeneity index and Conformity index. Findings: 3DCRT planning with oesophagus delineation can be considered as a method to reduce oesophageal dose and the acute oesophageal toxicity during radiotherapy for carcinoma breast.

Effect of Change in the Neck Position on Dosimetric Parameters of the Oesophagus in Breast Cancer Patients Undergoing Supraclavicular Irradiation

“…D mean was 14•11±4•24Gy in the without oesophagus delineation group. A higher mean dose and V 15 in their study may be due to the contouring oesophagus at risk as they delineated the oesophagus from the room caudal border of the cricoid cartilage to the lower border of supraclavicular PTV (13) .…”

Association of Radiation-Induced Acute Esophagitis With Dosimetric Parameters of Oesophagus in Breast Carcinoma Patients Receiving Supraclavicular Nodal Irradiation

“…The left SCF is closer to the esophagus and may overlap it because of the esophagus's slight deviation to the left during its descent. In contrast to the right-sided SCF, this may lead to higher radiation dosages reaching the esophagus [ 23 ]. During our study, we found that the left side of the esophagus had higher D max and D mean values (6.7±2.1 Gy and 39.2±1.5 Gy, respectively) than the right side.…”

“…This occurrence could be explained by the left-sided position of the esophagus relative to the SCF. Bhaskaran et al's study reveals that left-sided breast cancer exposes the esophagus to more radiation than right-sided breast cancer, which might cause an imbalance in the radiation dose that these two regions receive [ 23 ]. If someone has regular esophageal shaping, the right amount of radiation exposure, close patient monitoring during RT for esophageal inflammation, and good treatment process management [ 24 ], it is less likely that they will develop esophagitis.…”

Prediction factors of radiation esophagitis in breast cancer patients undergoing supraclavicular radiotherapy

“…This could result in more dose received to the esophagus compared to the right side, this was in accordance with the result of a study carried out by Bhaskaran et al ., which reported that the dose delivered to esophagus is higher in the left-sided breast cancer. [ 20 ]…”