Palliative lung radiotherapy at the Christie: audit of prescribing practice and survival analysis

Abstract

Introduction: Choosing the optimal palliative lung radiotherapy (RT) regimen is challenging. The Royal College of Radiologists (RCR) guidance recommends treatment stratification based on patients' performance status (PS). The aim of palliative treatment is to alleviate symptoms, but evidence suggests higher radiotherapy doses are associated with survival benefits. Here, we present the effects of fractionation regimen and additional factors on the survival of palliative lung cancer radiotherapy patients. Methods: An audit comparing palliative non-small cell lung cancer (NSCLC) radiotherapy prescription with RCR guidance was conducted in a retrospective patient cohort (n=422) treated between 2013 and 2018 at the Christie. Multivariable analysis of the prognostic significance of baseline patient characteristics and treatment prescription on overall survival was performed on a combined NSCLC and small cell lung cancer patient cohort (n=422). The percentage of patients dying within 30 days of treatment was calculated. Covariates investigated included: sex, age, PS, histology, comorbidities, stage, tumour location, tumour side, smoking status, pack year history, primary RT technique and fractionation scheme (8 Gy/1 F, 10 Gy/1 F, 20 Gy/5 F, 30 Gy/10 F). Results: 80.8% of patients were treated according to RCR guidance. 2.6% good PS patients were under-dosed (i.e. lower dose and/or fractionation compared to RCR recommendations) and 16.6% poor PS patients were over-dosed. 85 patients (9.2%) died within 30 days of treatment. Univariable analysis revealed that PS (p<0.0001), fractionation scheme (p<0.0001) and comorbidities (p=0.03) were significantly associated with survival. Univariable subset analysis results are displayed in Fig. 1. Multivariable analysis: better PS (p=0.003) and increased dose/fractionation regimens of up to 30Gy/10F (p<0.0001) were the only covariates that significantly correlated with increased survival. Conclusion: RCR guidance for palliative lung radiotherapy was followed for the majority of patients. Increased fractionation regimens (up to and including 30Gy/10F) were associated with better survival regardless of performance status.