ESTRO 2020 Abstract book

S587 ESTRO 2020

Material and Methods Pts with measurable primary tumor (size 2 to 5 cm) and unresectable stage III NSCLC, PS 0 or 1, eligible for CCRT were screened. Primary peripheral tumor had to be located at least 2 cm from the mediastinum and should not have receive more than 10 Gy during CCRT. Pts were included after completion of CCRT. Pts received 4 cycles of cisplatin and oral vinorelbin (1 cycle induction CT and 3 cycles concurrently with RT). Rt delivered 66 Gy in 33 fractions either with 3D conformal RT or IMRT. SBRT was planned between 1 and 4 weeks after completion of RT and delivered 50 Gy/ 5 fractions or 54 Gy/3 fractions on 80% isodose, depending on the size and location of the primary tumor. Primary endpoint was loco-regional control (LRC) rate at 6 months on chest CT and/or PET. Secondary endpoints were toxicity, OS and PFS. Considering a LRC rate of 55% at 6 months, 70 pts were needed. Results 25 pts were screened between 12/2015 and 04/2018 in 11 institutions. 6 pts did not receive SBRT (1 for investigator decision, 3 for beam, dose or volume RT inadequacy, 1 for pulmonary infection, 1 for chemo-related toxicity), leaving 19 pts for the analysis. Median age was 60.9 years (38–76), 15 pts were male (78.9%), 13 pts were PS0 (68.4%), 14 pts had adenocarcinoma (73.7%), and stages were IIIA in 10 pts (52.6%) and IIIB in 9 pts (47.4%). All pts were current or previous smokers. The median follow up time was 22.7 months (3.3-27.6). Toxicity was mild during SBRT: 1 pt had Gr1 cough and Gr1 hemoptysis. After completion of SBRT, 1 pt had Gr3 pulmonary toxicity, 1 pt had Gr2 bronchial stenosis and 1 pt had Gr1 cough. At the time of analysis, 8 pts experienced progressive disease and 5 had died. Progression was metastatic only in 3 pts, metastatic and regional in 2 pts, metastatic and local in 2 pts, metastatic and loco-regional in 1 pt. No patient had isolated recurrence in irradiated sites. Conclusion Combining CCRT and SBRT is feasible and safe. The recruitment of this study was stopped before completion, firstly because of the approval of adjuvant durvalumab after CCRT, which was not anticipated in the design, and secondly because of the small number of stage III NSCLC patients presenting with a peripheral tumor accessible to SBRT. PO-1016 Efficacy and safety profile of Stereotactic Ablative Radiotherapy (SABR) for multiple lung primaries A. Littlejohns 1 , T. Janjua 1 , P. Murray 1 , P. Jain 1 , K. Clarke 1 , P. Dickinson 1 , M. Teo 1 , A. Saha 1 , K. Franks 1 , F. Sun 1 1 Leeds cancer centre, Oncology, Leeds, United Kingdom Purpose or Objective A significant proportion of patients with early stage NSCLC are demonstrated to have multiple primary lung cancers. The mainstay treatment is surgical resection but for those who are ineligible, SABR is the alternative curative treatment. SABR to multiple lung sites has been offered to selected patients presenting with multiple primary lung cancers. Extensive evidence exists in support of SABR for solitary lung primaries. However, data is more limited in the context of multiple primaries. In this study our primary aim was to evaluate the efficacy of SABR to two synchronously diagnosed primary lung cancers. The secondary aim was to evaluate the associated safety profile. Material and Methods Electronic health records of patients treated at a large UK cancer centre with SABR to two synchronously diagnosed lung primaries, between January 2010 to December 2016 were retrospectively reviewed. Patient and tumour demographics were collected. Post treatment radiation pneumonitis and oesophagitis data were collected.

Conclusion Compared to a breath hold without any support, NHFT significantly increased the duration of a BH by a factor 3 (from 43 sec to 106 sec) during the training session. 75% of treated NSCLC patients were able to tolerate the irradiation in breath hold with NHFT for the whole treatment. Subjective tolerance of the device was excellent. This device offers a promising solution to treat lung cancer patients in BH both for photon and proton RT. PO-1015 SBRT after CT-RT for stage III unresectable NSCLC with peripheral primary tumor (GFPC 01-14 study) I. Martel-Lafay 1 , S. Danhier 2 , E. Blanc 3 , I. Monnet 4 , O. Gallocher 5 , N. Salem 6 , H. Berard 7 , O. Bykicki 8 1 Centre Léon Bérard, Radiation Therapy Department, Lyon, France ; 2 Centre François Baclesse, Radiation Therapy Department, Caen, France ; 3 Centre Léon Bérard, Clinical Research and Statistics Department, Lyon, France ; 4 Centre Hospitalier Intercommunal, Chest Department, Créteil, France ; 5 Clinique Pasteur, Radiation Therapy Department, Toulouse, France ; 6 Institut Paoli Calmette, Radiation Therapy Department, Marseille, France ; 7 HIA Saint Anne, Chest Department, Toulon, France ; 8 HIA Percy, Chest Department, Clamart, France Purpose or Objective Concurrent chemoradiation (CCRT) is the standard treatment for unresectable stage III NSCLC. When considering stage III pts presenting with a peripheral primary tumor, irradiated volume may include a large part of normal lung, which could result in severe radiation pneumonitis. SBRT is known to provide excellent control rates in early stage NSCLC. In this study, we evaluated the feasibility of delivering SBRT to the primary tumor, after CCRT for nodal hilar or mediastinal involvement, with the aim of minimizing the risk of severe radiation toxicity.