A Prognostic Tool to Estimate the Risk of Pneumonitis in Patients Irradiated for Lung Cancer

Background/Aim: Radiotherapy of lung cancer can lead to pneumonitis. This study aimed to identify risk factors and create a prognostic tool. Patients and Methods: Sixteen factors were evaluated in 169 patients irradiated for lung cancer including age, sex, lung function, primary tumor/nodal stage, histology, tumor location, surgery, systemic treatment, radiation volume, total dose, mean dose to ipsilateral lung, history of another malignancy, pack years, chronic inflammatory disease, and cardiovascular disease. Results: Forty-one patients experienced pneumonitis. Significant associations were found for total doses >56 Gy (p=0.023), mean lung doses >20 Gy (p=0.002) or >13 Gy (p<0.001), and chronic inflammatory disease (p=0.034). Considering mean lung dose and chronic inflammatory disease, scores were 2, 3, 4, or 5 points. Pneumonitis rates were 0% (0/35), 24% (14/58), 32% (21/66), and 60% (6/10) (p=0.001), respectively. Conclusion: Based on significant risk factors, a prognostic tool was developed that can help estimate the risk of pneumonitis and contribute to personalized follow up of patients.