Monte Carlo Applications for Local Treatment Healthcare Usage Simulations

The Malthus programme produces a model for the local and national level of radiotherapy demand for use by commissioners and radiotherapy service leads inEngland. The accuracy of simulation is dependent on the population cancer incidence, stage distribution and clinical decision data used by the model. In order toquantify uncertainty in the model, a global sensitivity analysis of the Malthus model was undertaken. As predicted, key decision points in the model relating tostage distribution and indications for surgical or non-surgical initial management of disease were observed to yield the strongest effect on simulated radio-therapy demand. The proportion of non-small cell lung cancer patients presenting with stage IIIB/IV disease had the largest effect on fraction burden in the fourmost common cancer types treated with radiotherapy, where a 1% change in stage IIIb/IV disease yielded a 1.3% change in fraction burden for lung cancerpatients. A 1% change in mastectomy rate yielded a 0.37% change in fraction burden for breast cancer patients. The model is also highly sensitive to changes inthe radiotherapy indications in colon and gastric cancer. Broadly, the findings of the sensitivity analysis mirror those previously published by other groups.Sensitivity analysis of the local-level population and cancer incidence data revealed that the cancer registration rate in the 50e64 year female population hadthe highest effect on simulation results. The analysis reveals where additional effort should be undertaken to provide accurate estimates of important pa-rameters used in radiotherapy demand models.2014 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.