ESTRO 2022 - Abstract Book

S658

Abstract book

ESTRO 2022

PD-0745 Radiation esophagitis in patients receiving hypofractionated post mastectomy radiotherapy

N. Vijayaraghavan 1 , M.K. K 2 , J. Mathew 3 , A. Menon 4 , V. Thovarayi 4 , P. Vedasoundaram 5

1 JIPMER, RADIATION ONCOLOGY, Pondicherry, India; 2 JIPMER, Radiation Oncology, Pondicherry, India; 3 JIPMER, RADIATION ONCOLOGY, PONDICHERRY, India; 4 JIPMER, Radiation Oncology, Pondicherry, India; 5 JIPMER, Radiation Oncology, JIPMER, India Purpose or Objective The cervical esophagus is in close proximity to the supraclavicular field. With the growing usage of the IMRT technique, we noticed more radiation esophagitis. We performed this study to correlate the dose-volume parameters and acute esophagitis resulting from hypo-fractionated radiotherapy Materials and Methods Sixty-seven post-mastectomy patients receiving hypofractionated radiation to the chest wall and supraclavicular field (SCF) were included in the study. The esophagus was contoured from the lower border of cricoid cartilage till 2 cm below the supraclavicular field. A total dose of 42.56 Gy in 16 fractions was prescribed to the PTV using the IMRT technique. Analysis of the dose-volume histogram data of the volume of the esophagus irradiated was performed. Spearman’s correlation was used to find an association between the dose received by the OAR and the grade of esophagitis. Patients were graded using Radiation Therapy Oncology Group acute morbidity scoring scale once a week during the treatment and until their symptoms had resolved. Patients having grade II and above acute radiation were subjected to an upper gastrointestinal endoscopy by the end of radiation therapy. The presence of radiation esophagitis was assessed and assigned an endoscopic score (Grade 0 - normal, Grade 1 - erythema, Grade 2 - erosion or sloughing, Grade 3 - ulcer, hemorrhage, or stricture). Results The mean (SD) age of the study population was 48 (9.5) years. The incidence of grade 2 and above acute esophagitis was 46.3 % [95% C.I 34.86- 58.08]. One patient developed grade 3 esophagitis. The mean time taken to develop grade 2 and above toxicity was 16 days. Patients who had grade 2 and above esophagitis experienced grade 1 toxicity three days before those who had a maximum grade 1 toxicity. Left breast cancer patients had a higher incidence of grade 2 toxicity. People who received Internal Mammary Node irradiation had increased grade 2 toxicity. (P=0.049). The mean length of the Esophagus in the SCF PTV field was 4.3 cm (±1.08). The mean (SD) of Esophagus Dmax was 43.5 (±2.9) Gy. The mean Dmean of the Cervical Esophagus was 30 Gy (±5.9). The incidence of grade 2 and above esophagitis was 83.8 % when the length of the esophagus in the SCF PTV was more than 4.0 cm (p= 0.005). When the Dmean of the cervical Esophagus was less than 30 Gy, V90% (V38.3Gy) < 10%, and V75% (V32Gy) < 30%, the incidence of grade 2 and above esophagitis was 20 %. UGI endoscopy revealed 60% had grade 1 and 30 % had grade 2 changes at the end of treatment. The cervical esophagus lies in close proximity to the SCF PTV. In IMRT, there occurs dose spillage which could explain the increased esophagitis noted in our study.

Conclusion Radiation esophagitis is of concern in patients receiving radiation to the supraclavicular field. Limiting the length of the esophagus in the SCF PTV and keeping the D mean of the cervical esophagus below 30 Gy can reduce the radiation esophagitis.

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