Frameless Image-Guided Stereotactic Body Radiation Therapy for Lung Tumors with 4-Dimensional Computed Tomography or 4-Dimensional Positron Emission Tomography/ Computed Tomography

Background/PurposeTo augment the accuracy of stereotactic body radiation therapy (SBRT), a variety of image guidance systems are used for patient positioning and target localization. Clinical outcomes evaluating these systems, especially frameless image-guided systems, are still limited. This article aims to describe and evaluate our frameless image-guided SBRT technique for lung tumors.MethodsBetween 2007 and 2009, 85 pulmonary tumors (50 primaries and 35 metastases) were treated with SBRT using daily image guidance for patient positioning and target localization in lieu of a body frame. Four-dimensional computed tomography (4DCT) or an in-house protocol for integrated 4D positron emission computed tomography (4DPET/CT) was used for planning simulation.ResultsMedian follow-up was 17 months (range, 4-42). Median overall survival (OS) was 31 months (95% CI, 26-34), and median local failure-free survival was 30 months (95% CI, 18-32). At last follow-up, 9 of 83 evaluable lesions failed locally. Actuarial local control at 24 months was 87% (95% CI, 75-98) and was significantly worse for metastatic lesions (95% vs. 74%; P = .045; log-rank test). No acute or late toxicities (grade ≥ 4) were observed.ConclusionsFrameless image-guided SBRT is a feasible, safe, and effective treatment for lung tumors.