ESTRO 38 Abstract book

S733 ESTRO 38

Adenocarcinoma- 31%, other- 14%. Median follow up was 3.2 years. Median overall survival 31.2 months (95% CI 21.9- 42.8). On treatment toxicity was tolerable with no treatment related deaths. 20% had local recurrence, 23% had distant metastases and 7% had local recurrence & distant metastases. 77% of patients were treated by Volumetric modulated arc radiotherapy (VMAT) plan and 23% by conventional plan. The larger the planning target volume (PTV) lesser the median overall survival.

in LC (p=0.45) DFS (p= 0.17) and OS (p=0.9) between the techniques. We found statistically significant improved in DFS in the major pathological response: HR 2.3 (95%CI 1.13-4.75) (p=0.02).

Conclusion Hypofractionated radiotherapy with chemotherapy was well tolerated in stage -3 NSCLC patients. Toxicity was minimal and no non-cancer death within 90 days of treatment. Overall median survival was superior to all arms in recently published international phase 3 trials. EP-1339 Clinical outcomes of stereotactic radiotherapy using flattening-filter-free in lung cancers T. Taweesakulvashra 1 , S. Kitpanit 1 , A. Songthong 1 , C. Chakkabat 1 , N. Amornwichet 1 , P. Alisanant 1 , C. Nantavithya 1 , C. Lertbutsayanukul 1 , K. Shotelersuk 1 , C. Khorprasert 1 , D. Kannarunimit 1 1 King Chulalongkorn Memorial Hospital- Chulalongkorn University, Division of Radiation Oncology- Department of Radiology, Bangkok, Thailand Purpose or Objective SBRT using FFF has been increasingly applied due to its benefits in escalating dose rate, short treatment time and less out-of-field dose, however, studies investigating outcomes and toxicities of this technique in lung cancers are lacking. Thus, we conducted a review to assess efficacy in terms of 2-year local control (LC), progression free survival (PFS), overall survival (OS) and treatment- related toxicities in patients with early-stage NSCLC and oligometastatic lung cancers. Material and Methods From February 2014 to July 2018, 101 patients underwent lung SBRT with FFF were retrospectively reviewed. All patients underwent SBRT with VMAT and unflatten beam using 6 and 10 MV photon. Patients with follow up period less than six months or lack of follow-up imaging were excluded. Dose and fractionation were selected from our institutional protocol. LC, PFS and OS were analyzed using Kaplan-Meier method. Early and late toxicities (6 months after SBRT) were evaluated. All target lesions were accounted for LC assessment.

Conclusion When used to treat NSCLC in the neoadjuvant setting, both IMRT/VMAT and 3DCRT produce comparable clinical and pathologic tumor-control outcomes. EP-1338 Hypofractionated Chemoradiotherapy for stage-3 Non-small cell Lung cancer- Single centre experience A. Patibandla 1 , N. Mohammed 1 , I. Brisbane 1 , P. McLoone 2 , J. Hicks 1 1 Beatson West of Scotland Cancer centre, Clinical Oncology, Glasgow, United Kingdom ; 2 University of Glasgow, Statistics, Glasgow, United Kingdom Purpose or Objective Concurrent chemoradiotherapy is standard of care for locally advanced stage-3 non-small cell lung cancer (NSCLC). Hypofractionated radical radiotherapy ( 5500cGy in 20 fractions over four weeks ) with chemotherapy (cisplatin & vinorelbine) has been proven safe and effective in a randomised phase -2 trial(SOCCAR trial). In this retrospective study we looked at our institutional experience of delivering this regimen. Material and Methods Electronic records were retrospectively reviewed for all stage-3 NSCLC patients who had SOCCAR regimen from January 2012 to December 2016. Data was censored on 31 st March 2018. Kaplan-Meier analysis was used to estimate median survival. Results Total of 163 patients, all the stage-3 NSCLC patients treated with SOCCAR regimen between January 2012 to December 2016. Median age- 63 years. All patients except one were staged by PET-CT prior to starting treatment. All were either ECOG performance status of 0 or 1. Squamous cell carcinoma- 55%,