Radiother Oncol 2015-10-01
Stereotactic ablative radiotherapy (SABR) for central lung tumors: Plan quality and long-term clinical outcomes.
Abstract
Background and purpose
Central lung SABR is less established due to toxicity concerns. We describe plan quality and clinical outcomes for patients treated with VMAT SABR using 8×7.5Gy.
Materials and methods
We studied 80 consecutive patients with primary NSCLC and PTV ⩽2cm from the proximal bronchial tree (PBT), treated between 2008 and 2013. Dosimetric data were compared with institutional guidelines and study protocols, and long-term clinical outcomes were analyzed.
Results
PTV V95% was 60Gy in 96% of patients. Dmax was ⩾60Gy in 40% of patients for PBT, 26.3% for aorta, 55% for heart, and 1.3% for trachea. Esophageal maximum Dmax was 58Gy. Mean lung V5Gy/V20Gy was 21/8%. 54 patients (68%) exceeded RTOG0813 Dmax for ⩾1 organ-at-risk (OAR), with 27 exceeding PBT Dmax. 5 of 78 patients (6.4%) with adequate follow-up information had grade 3 toxicity. Grade 4 toxicity was not observed. Treatment-related death was considered possible (n=3) or likely (n=3) in 6 patients (7.5%). With median follow-up of 47months, 3-year survival was 53%, compared with 57% for 252 peripheral tumors treated with 3/5-fractions SABR in the same period (p=0.369).
Conclusions
Although a substantial proportion of central SABR patients received ⩾60Gy to OARs, the 3-year survival was no different from peripheral SABR.
