Oesophageal Dose?Volume Parameters and Acute Radiation Oesophagitis in Non-Small Cell Lung Cancer Treated With Definitive Intensity-Modulated Radiotherapy: A Prospective Observational Study

Abstract

Author(s): K C Jyothish*, C Ajithaashree, C Saranya, R Giridharan and S Jeva

Background: Acute radiation oesophagitis can impair oral intake, treatment adherence and quality of life during definitive thoracic radiotherapy. Prospective data on oesophageal dose–volume predictors in patients treated with intensity- modulated radiotherapy (IMRT) in Indian practice are limited. Methods: Thirty consecutive patients with stage I–III non-small cell lung cancer (NSCLC) receiving definitive IMRT to 60 Gy in 30 fractions were prospectively evaluated. Oesophageal Dmean, D2cc, V50 and V60 were extracted from planning dose–volume histograms. Acute oesophagitis was graded weekly using Radiation Therapy Oncology Group (RTOG) criteria, and dysphagia was assessed with the Dysphagia Symptom Questionnaire (DSQ). Spearman correlation and exploratory receiver operating characteristic (ROC) analyses were performed. Results: Any-grade oesophagitis occurred in 27/30 patients (90.0%); grade 2 and grade 3 events occurred in 15 (50.0%) and 6 (20.0%), respectively, with no grade 4 events. Mean Dmean, D2cc, V50 and V60 were 25.1 ± 8.0 Gy, 57.6 ± 12.6 Gy, 9.6 ± 6.0 cm³ and 4.0 ± 2.6 cm³. All four metrics increased with peak RTOG grade (p < 0.001). D2cc showed the strongest correlation with peak grade (r? = 0.894, p < 0.001). The apparent area under the curve for grade 3 oesophagitis was 0.958 for each metric, with exploratory thresholds of 31 Gy, 68 Gy, 13 cm³ and 5.5 cm³, respectively. Conclusion: Higher mean and high-dose oesophageal exposure were strongly associated with acute oesophagitis during definitive IMRT. D2cc and V60 may complement Dmean in routine plan evaluation. Study-specific thresholds are exploratory and require external validation.

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