ESTRO 2020 Abstract Book

S542 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.

Survival outcomes were calculated using SPSS statistics software. Results 20 patients have been identified and included in the study. All patients presented with two synchronously diagnosed lung cancer and received SABR for both lesions. Patient and tumour demographics are summarised in table 1. Distribution of lung cancers is presented in picture 1. 65% of lesions were treated with 55 Gray in 5 fractions, 28% with 60 Gray in 8 fractions, 7% with 54 Gray in 3 fractions. 90% of patients received both SABR treatments within one month of each other. One grade 2 pneumonitis occurred after treatment. No oesophagitis occurred. Median overall survival was 718 days. Median progression free survival was 565 days. Overall local control was 87.5%. Picture 1

Table 1

Conclusion SABR to synchronously diagnosed early lung cancer is well tolerated. Local control and survival outcomes are comparable with existing literature. PO-1017 Poor Diffusing Capacity for Carbon Monoxide (DLCO) is associated with worse survival post SABR F. Sun 1 , P. Jain 1 , P. Murray 1 , K. Clarke 1 , P. Dickinson 1 , M. Teo 1 , A. Saha 1 , K. Franks 1 1 Leeds cancer centre, Oncology, Leeds, United Kingdom Purpose or Objective Stereotactic ablative radiotherapy (SABR) is the standard non-surgical management for peripheral early lung cancers. Existing literature suggest SABR is safe in patients with poor lung function. This study evaluates the effect of lung function on survival outcomes for patients treated with SABR.