Radical radiotherapy (RT) and chemoradiotherapy (CRT) in non-small cell lung cancer (NSCLC): Outcomes from a regional cancer network

ABSTRACT

Background: This is a retrospective review of outcomes and predictive factors for radical RT for NSCLC in our network. Technological advancement in RT has enabled treatment of larger tumours. SOCCAR (55Gy in 20 fractions) is the most used regime at our centre. This is a timely review in the context of COVID-19, with a renewed interest in shorter RT schedules. Methods: Data for patients who received RT or CRT for Stage I-III NSCLC from 2016-2018 (prior to introduction of adjuvant Durvalumab – NICE approved in 2018) was reviewed at North Middlesex University Hospital, London. Data included smoking history, lung function, planning parameters (PTV, Mean heart dose (MHD), V20 and V5 lung), relapses and deaths. Outcomes were demonstrated as overall survival (OS) and progression free survival (PFS) through Kaplan-Meier analyses. Progression was defined from follow-up imaging or clinical documentation. Results: 90 patients were analysed. Median follow-up time was 16 months. Median age was 72. 60 patients received 55Gy (66%) and 30 received 60-66Gy (33%). 32 patients received concurrent CRT (cCRT-36%), 13 received sequential CRT (sCRT-14%) and 45 received RT alone (50%). 21 patients had early disease (Stage I+II,23%) and 69 had Stage III disease (77%). Median PTV was 304 mm3 and median MHD was 6.65Gy. For all patients, median OS (mOS) was 23 months. Median PFS (mPFS) was 12 months. 1, 2 and 3 year OSR was 72%, 47% and 30% respectively. In those aged over 70, mOS was 23 months and mPFS was 12. For cCRT, mOS was 26 months and mPFS was 14. For sCRT, mOS was 13 months and mPFS was 13. RT alone mOS was 22 months and mPFS was 10. mOS for the cCRT group using 60-66Gy was 26 months and was not reached for 55Gy. mPFS for 60-66Gy and 55Gy was 12 and 15 months respectively. In those aged over 70-1,2 and 3 year OSR was 83%,70% and 50% respectively. FEV1% predicted was associated with OS (HR 0.98, 95% CI 0.97-0.99, p=0.04). Further analysis was performed looking at smoking history, performance status, pathology and gender. Conclusions: Our data confirms that cCRT is an effective treatment for NSCLC (regardless of schedule and age) with comparable outcomes to contemporary CRT trials. Patient screening and regimen choice is key to good outcomes, as apparent in the trends within our data. Legal entity responsible for the study The authors. Funding: Has not received any funding. Disclosure All authors have declared no conflicts of interest.