Renin-Angiotensin System Inhibitors Might Help to Reduce the Development of Symptomatic Radiation Pneumonitis After Stereotactic Body Radiotherapy for Lung Cancer

The use of a renin-angiotensin system (RAS) inhibitor might prevent the occurrence of symptomatic radiation pneumonitis (RP) after radiotherapy for lung tumors. Stereotactic body radiotherapy (SBRT) is often delivered to patients not suitable for surgery; however, it might not be tolerated because most of these patients have advanced age and/or comorbidities. The use of a RAS inhibitor was associated with a reduced occurrence of grade >= 2 RP after SBRT for lung lesions. Introduction: The purpose of the present study was to evaluate the role of renin-angiotensin system (RAS) inhibitors in preventing symptomatic radiation pneumonitis (RP) after stereotactic body radiotherapy (SBRT). Materials and Methods: The data from 158 patients with a solitary lung lesion treated with 1 to 3 fractions of SBRT from December 2008 to July 2014 were retrospectively analyzed. The incidence of RP was evaluated according to the Common Toxicity Criteria for Adverse Events, version 4. The use of angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) was analyzed to assess for possible correlations with the development of grade >= 2 RP. The patient and dosimetric variables were also assessed. Results: After a median follow-up period of 13.8 months (range, 3.2-55.0 months), 22 patients had developed grade >= 2 RP. Patients with peripheral lesions, favorable dosimetric data, and ACEI and/or ARB use had a reduced risk of symptomatic RP. In unadjusted and adjusted multivariate analyses, ACEI and/or ARB intake and the dosimetric variables were statistically significant factors. In a secondary analysis, the use of ACEIs and ARBs among patients with a greater planning target volume and higher dosimetric values correlated with a reduced risk of symptomatic RP. Conclusion: The use of a RAS inhibitor was associated with a decreased incidence of symptomatic RP among patients undergoing SBRT for lung lesions. Patients with higher dosimetric values had a reduced risk of grade >= 2 RP with ACEI and ARB use.