No differences in radiological changes after 3D conformal vs VMAT-based stereotactic radiotherapy for early stage non-small cell lung cancer

Objective:To compare patterns of acute and late radiological lung injury following either 3D conformal or image-guided volumetric modulated arc therapy stereotactic radiotherapy for Stage I non-small-cell lung cancer.Methods:We included 148 patients from a prospective mono-institutional stereotactic body radiation therapy (SBRT) series (time interval 2004–2014), treated with prescription BED10 Gy (at 80%) in the range 100–120 Gy. The first 95 patients (2004–2010) were planned with 3D-CRT, with a stereotactic body frame. The second cohort (2010–2014) included 53 patients, planned with volumetric IMRT on a smaller planning target volume generated from a patient’s specific internal target volume, with a frameless approach through cone-beam CT guidance. Acute and late radiological modifications were scored based on modified Kimura’s and Koenig’s classifications, respectively.Results:Median follow-up time was 20.5 months. The incidence of acute radiological changes was superimposable between the groups: increa...