Risk factors for symptomatic radiation pneumonitis after stereotactic body radiation therapy (SBRT) in patients with non-small cell lung cancer. (March 2021)

• Record Type: Journal Article
• Authors: Liu, Yongmei; Wang, Weili; Shiue, Kevin; Yao, Huan; Cerra-Franco, Alberto; Shapiro, Ronald H.; Huang, Ke Colin; Vile, Douglas; Langer, Mark; Watson, Gordon; Bartlett, Greg; Ai, Huisi; Sheski, Francis; Jin, Jian-Yue; Zellars, Rich; Fu, Pingfu; Lautenschlaeger, Tim; Kong, Feng-Ming (Spring)
• Is Part Of: Radiotherapy and oncology. Volume 156(2021)
• Page Start: 231
• Page End: 238
• Publication Date: 2021-03
• Subjects: Lung cancer -- Stereotactic body radiation therapy -- Radiation pneumonitis -- Risk factor; Oncology -- Periodicals; Radiotherapy -- Periodicals; Tumors -- Periodicals; Medical Oncology -- Periodicals; Neoplasms -- radiotherapy -- Periodicals; Radiotherapy -- Periodicals; Radiothérapie -- Périodiques; Cancérologie -- Périodiques; Tumeurs -- Périodiques; Electronic journals; 616.9940642
• DOI: 10.1016/j.radonc.2020.10.015
• Languages: English
• ISSNs: 0167-8140

Abstract

Highlights: Clinical and dosimetric risk factors for symptomatic RP after SBRT were analyzed in a large series of patients. Respiratory comorbidity, previous lung radiation, right lung location, BED10 of the prescription dose, MLD and V20 of total lungs, and MLD of ipsilateral lung were significant factors for higher risk of symptomatic RP. Should the risk of RP2 be limited less than 10%, the mean doses of total lung and ipsilateral lung be constrained to less than 6 Gy and 20 Gy, respectively. Abstract: Background and purpose: Radiation pneumonitis (RP) can be a potential fatal toxicity of stereotactic body radiation therapy (SBRT) for medically inoperable non-small cell lung cancer (NSCLC). This study aimed to examine the risk factors that predict RP and explore dosimetric tolerance for safe practice in a large institutional series of NSCLC patients. Materials and methods: Patients with early-stage and locally recurrent NSCLC who received lung SBRT between 2002 and 2015 formed the study population. The primary endpoint was grade 2 or above radiation pneumonitis (RP2). Lungs were re-contoured consistently by one radiation oncologist according to the RTOG atlas for organs at risk. Dosimetric factors were computed consistently with exclusion of gross tumor volume of either ipsilateral, contralateral, or total lungs. Results: A total of 339 patients were eligible. With a median follow-up of 47 months, RP2 was recorded in 10% patients. History of respiratory comorbidity, previous thoracic radiation, right lung location, mean lung doses of total or ipsilateral lung, and total lung volume receiving 20 Gy were all significantly associated with the risk of RP2. The dosimetric parameters of contralateral lung, including mean dose and volume receiving more than 5, 10, and 20 Gy, were not significantly associated with RP2 (ps > 0.05). A model of combining significant clinical and dosimetric factors had a predictive accuracy AUC of 0.76. According to this model, RP2 can be limited to <10% should the patient have no previous lung radiation and the mean dose of total and ipsilateral lungs be kept less than 6 Gy and 20 Gy, respectively. Conclusion: Dosimetric factors of total or ipsilateral lung together with important clinical factors were significant risk factors for symptomatic radiation pneumonitis after SBRT. Constraining mean lung dose can limit clinically significant lung toxicity.