34 Audit of histological confirmation of malignancy prior to stereotactic radiotherapy (SABR) to treat early-stage non-small cell lung cancer

Abstract

Introduction Stereotactic ablative radiotherapy (SABR) offers a non-invasive treatment approach for medically-inoperable early-stage non-small cell lung cancer (esNSCLC) with control rates?>85% (1). Biopsy is not always feasible, and some patients are diagnosed clinically, relying on imaging and predictive models such as Herder score. Methods We carried out a retrospective cohort audit at North Middlesex University Hospital (NMUH) analysing biopsy rates of patients treated with SABR for esNSCLC to compare to the 2022 National Lung Cancer Audit (58-94% for esNSCLC, PS 0-1). Electronic records of patients treated with SABR for esNSCLC between June 2020 and December 2023 were reviewed. Data on referral hospital, biopsy performed, reasons if biopsy was not performed, TNM stage, herder score, lung function, comorbidities and performance status were collected. Results 82 evaluable patients were treated with SABR for esNSCLC. Mean age was 78 (56-90). 23 (28%) patients had histological confirmation of NSCLC obtained via CT-guided biopsy. Patients diagnosed at Chase Farm Hospital had a higher biopsy rate 67% (14/21) compared to 25% (7/28) at NMUH and 6% (2/33) at Princess Alexandra Hospital. Reasons for not performing a biopsy was 35% due to comorbidities, 46% poor lung function, 14% tumour location, 2% following MDT decision and 3% other reasons. Biopsy rate was highest in patients treated in 2020 (45%) followed by 2021 (32%), 2022 (26%) and lowest in 2023 (19%). Conclusion Our audit demonstrates variation between referral sites on obtaining histopathological diagnosis prior to SABR in esNSCLC and declining biopsy rates over the past 4 years. Further data analysis and review of institutional guidelines is required to understand this variation and trend. Disclosure No significant relationships