Reduced frequency and severity of radiation esophagitis without marginal failure risk by contralateral esophagus sparing IMRT in stage III non-small cell lung cancer patients undergoing definitive concurrent chemoradiotherapy

Purpose: Radiation esophagitis is frequent and annoying toxicity in high dose thoracic radiation therapy. Contalateral esophagus sparing intensity modulated radiation therapy (CES-IMRT) has been proposed to mitigate this problem, and this is to report the impact of CES-IMRT in definitive concurrent chemoradiotherapy (dCCRT) for lung cancer patients. Materials and methods: From January 2021 till May 2023, 183 stage III non-small cell lung cancer patients underwent dCCRT. Esophagus was located within 1 cm from internal target volume in 159 patients. We comparatively evaluated the frequency and severity of esophagitis by pain-killer usage, analgesic quantification algorithm (AQA) score, and failure patterns in 159 CES-necessary patients. Results: All patients underwent dCCRT (66 Gy in 30 fractions with concurrent chemotherapy). Actual CES-IMRT application was determined based on the discretion of responsible radiation oncologists: CES-applied in 41 patients; and CES-unapplied in 118. CES-applied patients experienced pain events less frequently (pain-killer usage: 53.7 % vs. 77.1 %, p = 0.008) and less severely (AQA score of 2–3: 39.0 % vs. 68.6 %, p = 0.002). On multivariate analyses, overlapping volume of esophagus and planning target (HR = 1.32, 95 % CI 1.12–1.55, p = 0.001) and CES-IMRT application (HR = 0.31, 95 % CI 0.13–0.76, p = 0.010) were associated with AQA score of 2–3 less frequently. There were no differences in failure pattern, progression-free survival, and overall survival. Conclusions: CES-IMRT application resulted in less frequent and less severe pain events without compromising oncologic outcomes. Further studies, preferably in a randomized fashion, would be desired.