Introduction The overall mortality rate for cancer has declined in Australia. However, socioeconomic inequalities exist and the out-of-pocket costs incurred by patients in Australia are high compared with some European countries. There is currently no readily available data set to provide a systematic means of measuring the out-of-pocket costs incurred by patients with cancer within Australia. The primary aim of the project is to quantify the direct out-of-pocket healthcare expenditure of individuals in the state of Queensland, who are diagnosed with cancer.

Methods and analysis This project will build Australia's first model (called CancerCostMod) of out-of-pocket healthcare expenditure of patients with cancer using administrative data from Queensland Cancer Registry, for all individuals diagnosed with any cancer in Queensland between 1 July 2011 and 30 June 2012, linked to their Admitted Patient Data Collection, Emergency Department Information System, Medicare Benefits Schedule and Pharmaceutical Benefits Scheme records from 1 July 2011 to 30 June 2015. No identifiable information will be provided to the authors. The project will use a combination of linear and logistic regression modelling, Cox proportional hazards modelling and machine learning to identify differences in survival, total health system expenditure, total out-of-pocket expenditure and high out-of-pocket cost patients, adjusting for demographic and clinical confounders, and income group, Indigenous status and geographic location. Results will be analysed separately for different types of cancer.

Ethics and dissemination Human Research Ethics approval has been obtained from the Townsville Hospital and Health Service Human Research Ethics Committee (HREC/16/QTHS/110) and James Cook University Human Research Ethics Committee (H6678). Permission to waive consent has been sought from Queensland Health under the Public Health Act 2005.