ESTRO 2024 - Abstract Book

S1573

Clinical - Lung

ESTRO 2024

9

Digital Poster

Gamma Knife radiosurgery for brain metastases in non-small cell lung cancer: a regional cohort study

Edward Christopher 1 , Robert Samuel 1 , Oliver Coen 1 , Oliver Jackson 1 , George Higginbotham 2 , Gavin Wright 1 , Stelios Theophanous 1 , Kevin Franks 1 , Michael Snee 1 , Pooja Jain 1 , Paul Hatfield 1 , Michael Flatley 1 , Katy Clarke 1 1 Leeds Cancer Centre, Leeds Teaching Hospitals NHS Trust, Leeds, United Kingdom. 2 Medicine, University of Bristol, Bristol, United Kingdom

Purpose/Objective:

Up to 50% of patients with non-small cell lung cancer (NSCLC) may develop brain metastases (BM) during the course of their disease. Gamma Knife stereotactic radiosurgery (GKRS) is an increasingly used treatment option for BM and offers high tumour control rates with favourable side-effect profiles. We aimed to: (1) describe survival following GKRS in patients with NSCLC-related BM in a UK cohort, using the latest iteration of the Graded Prognostic Assessment (GPA) index specifically adapted for NSCLC and including programmed death ligand-1 (PD-L1); (2) externally validate this GPA index on a UK cohort undergoing GKRS.

Material/Methods:

We included all consecutive patients aged ≥16 years diagnosed with NSCLC -related BM from March 2009 to November 2022 who underwent GKRS at a regional neuro-oncology centre. Leeds Gamma Knife Centre was first established in 2009 and is one of only four centres in the UK to deliver stereotactic radiosurgery using Gamma Knife Icon. Data including histology, number and volume of BM, and mutation profiles were retrospectively ascertained from electronic patient records. The 2022 iteration of the GPA index was used to describe overall survival following diagnosis of BM (OS).

Results:

426 patients were included in this study. Median age was 67 years (IQR 58-72) and 56.1% were female. 62.7% had adenocarcinoma. Median GPA score was 2.5 (IQR 2.0-3.0) and median OS following BM diagnosis was 11.9 months (IQR 5.5-22.6). In adenocarcinoma, the median OS following BM diagnosis in the four prognostic groups were 6.1 months (IQR 3.4-11.5) in GPA 0.0-1.0, 13.5 months (IQR 6.6-24.2) in GPA 1.5-2.0, 17.2 months (IQR 8.9-29.8) in GPA 2.5-3.0, and 31.2 months (IQR 23.7-37.7 months) in GPA 3.5-4.0 (c-index 0.61, p<0.0001) ( Figure 1 ). In non adenocarcinoma, the median OS following BM diagnosis in the four prognostic groups were 4.8 months (IQR 3.5 8.3) in GPA 0.0-1.0, 5.8 months (IQR 2.8-15.5) in GPA 1.5-2.0, 8.9 months (IQR 5.0-20.3) in GPA 2.5-3.0, and 9.6 months (IQR 4.8-22.3) in GPA 3.5-4.0 (c-index 0.55, p=0.018) ( Figure 2 ).