Lung stereotactic ablative radiotherapy (SABR): dosimetric considerations for chest wall toxicity

Objective:To investigate chest wall pain in patients with peripheral early stage lung cancer treated with stereotactic ablative radiotherapy (SABR), and to identify factors predictive of Common Terminology Criteria of Adverse Events Grade 2 + chest wall pain.Methods:Patients who received 55 Gy in five fractions were included. A chest wall structure was retrospectively defined on planning scans, and chest wall dosimetry and tumour-related factors recorded. Logistic regression was performed to identify factors predictive of ≥Grade 2 chest wall pain.Results:182 patients and 187 tumours were included. There were 20 (10.9%) episodes of ≥Grade 2 chest wall pain. Multivariate logistic regression demonstrated that the maximum dose received by 1 cm3 of chest wall (Dmax1 cm3) and tumour size were significant predictors of ≥Grade 2 chest wall pain [Dmax1 cm3 odds ratio : 1.104, 95% confidence interval : 1.012–1.204, p = 0.025; tumour size (mm) odds ratio : 1.080, 95% confidence interval : 1.026–1.136, p = 0.003]. Th...