P2.05-019 Stereotactic Body Radiotherapy (SBRT) for Central Lung Tumors: The Experience of Florence University-Careggi Hospital Radiotherapy: Topic: Clinical Outcome

Abstract

Stereotactic body radiotherapy (SBRT) for central lung tumors, defined as tumor within 2 cm or touching the zone of the proximal bronchial tree or tumors immediately adjacent to the mediastinal or pericardial pleura (Adebahr S. et al. BJR 2015) is debated because of toxicities to organs at risk. No evidences from phase III trial are available. From 2010 to 2015, 45 central lesions in 40 pts were treated with SBRT. 14 lesions were primary lung cancer (PLC), 31 were lymphoadenopathies (LAP). PLC were treated with volumetric arc Therapy (VMAT) in 9 cases and 5 with Cyberknife®. LAP were treated with VMAT in 12 cases, with IMRT (step and shoot) in 10 and with Cyberknife® in 9 cases. Prescribed doses varied between 18 and 60 Gy (1-8 fractions) with median BED of 65 Gy (37,5-105 Gy). We evaluated Overall Survival (OS), Progression Free Survival (PFS) and Disease Specific Survival (DSS) using Kaplan-Meier method and treatment related toxicities using CTCAE version 4.0. Median age was 62 years (48-86), 26 male and 14 female. PS was 0 in 9 pts, 1 in 21, 2 in 10 pts. Histology was available in all series and consisted of primary NSCLC (32 adenocarcinoma, 12 squamous cell carcinomas, 1 neuroendocrine tumor). 41 PLC were less than 2 cm from proximal bronchial tree, 4 PLC were immediately adjacent to the mediastinal or pericardial pleura. Tumor diameter was 10 to 60 mm with a median of 31 mm. Median follow up was 14,5 months. OS and DSS were 86.5% at 1 year, 55.6% at 2 years, and 49,4% at 3 years. PFS was 48,6% at 1 year, 24,1% at 2 years, and 12% at 3 years. 35 pts showed no acute toxicity; in 5 pts we recorded grade 1-2 esophagitis, in 2 pts grade 2 cough, in 2 pts, grade 1 asthenia. Chronic toxicity was present in 2 pts as grade 2 esophagitis. SBRT is confirmed to be a safe and effective strategy for central lung tumors. The majority of patients in the first part of our series was treated with low doses compared to current doses. Nevertheless 23 patients had clinical benefit from the treatment without life-threatening toxicities. Further studies are needed to establish the efficacy and safety of SBRT in central lung lesions.