Purpose/Objectives: Although radiotherapy technology is advancing rapidly, the availability of some new techniques such as Volumetric Modulated Arc Therapy (VMAT) remains low in Brazil due to their high implementation costs. Others such as SABR are still not covered by any health insurers in the country. The aim of this study is to report the preliminary clinical outcomes and toxicity of SABR delivered to early stage NSCLC and lung oligometastases using VMAT without a rigid imobilization system.Materials/Methods: Between March 2012 and November 2013, a total of 20 lung lesions were treated with SABR in 18 patients (16 by VMAT and 2 by 3D conformal technique). Among these lesions, 13 (65%) were peripheral and 7 (35%) were centrally located. Histology was proven in 17 patients (12 adenocarcinoma, 4 squamous cell carcinoma, 4 others). Median age was 75 years old (53 - 88). Serial PET scans and/or CT scans confirmed local control (LC). No 4DCT was used, instead ins-expiration technique or slow imaging acquisition using a conventional CT scan were employed. The dose/fractionation regimes most used were: 50-60 Gy in 5 fractions (BED 100-132 Gy10) and 60Gy in 8 fractions (BED 105 Gy10). Median ITV-PTV margin was 5 mm. Dose was prescribed to the median 97% isodose. Cone-beam CT was used for lesion localization and no fiducials were utilized. All patients were treated using a low-cost and simple setup: thin mattress, wing board and knee support.Results: The median follow-up was 12 months (1 - 19). Two patients died, giving a crude overall survival rate of 89%. The cause of death was progression of disease in 1 patient. There was evidence of in-field disease progression in only 1 lesion giving a crude local control rate of 95%. This local progression occurred in the lesion located close to the diaphragm on a patient with 2 primary lung lesions. Treatment was well tolerated and there were no interruptions because of acute toxicity. Pulmonary late complication of NCI-CTC grade ≥3 was noted in 1 patient who had a single lung.Conclusions: SABR using VMAT is a feasible and well-tolerated treatment in early stage NSCLC and for selected patients with lung oligometastatic disease. Due to the inexpensive setup and fast delivery provided by VMAT, which maximized the number of patients treated per machine, individual costs were significantly reduced thus making it feasible for patients to privately afford SABR in our reality. Although no 4DCT was used, LC rates were excellent in this series. Nonetheless, a longer follow up is needed to confirm our findings.
Morikawa, L,
Anderson, E,
Stereotactic Ablative Body Radiation Therapy (SABR) Using Volumetric Modulated Arc Therapy to Early Stage Non-small Cell Lung Cancer (NSCLC) And Lung Oligometastases. Brazilian Single Institution Early Experience and Clinical Outcomes. Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL.
http://archive.rsna.org/2014/14042701.html
