Updating the Malthus Programme decision tree for nonsmall cell lung cancer

Abstract

Introduction: The Malthus Programme models radiotherapy demand by combining data on cancer incidence with clinical decision trees detailing indications and dose-fractionation for radiotherapy. Since the last model update in 2017, we observe widespread implementation of hypofractionated stereotactic ablative radiotherapy (SABR) and a trend towards more aggressive treatment of patients with oligometastatic disease. We assess the impact of recent changes in clinical practice on radiotherapy demand for non-small cell lung cancer (NSCLC) across England in the latest model. Methods: The NSCLC decision tree was updated based on evidence for new radiotherapy indications and dose-fractionation schedules, as well as estimates of stage distribution and relative use of alternative management options. These were derived from literature searches, relevant guidelines, discussion with clinical oncologists, public databases and National Lung Cancer Audit data. Results: The main updates to NSCLC radiotherapy practice have been the implementation of SABR for early-stage disease, increasing utilisation of surgery, and radical thoracic radiotherapy treatment for patients with cerebral oligometastatic disease. The proportion of NSCLC patients receiving radiotherapy (appropriate rate of radiotherapy: ARR) decreased by 3% since the 2017 model. This was principally due to an increase in surgery as opposed to definitive radiotherapy for Stage III disease. The overall decrease in ARR masks the extra patients with Stage IV disease now receiving radical radiotherapy. Fraction burden decreased by 15%, reflecting both the reduced ARR and increasingly hypofractionated schedules, particularly for early-stage NSCLC. Conclusions: Use of SABR for early-stage NSCLC, combined with increasing resection rates for Stage III disease, seem to have reduced fraction demand. However, our estimate of rise in resection rate may have been affected by the lack of national audit data available to inform our original model. Future fraction burden may change as early detection fuels demand for SABR, and more indications for radiotherapy for oligometastatic disease emerge.