Economic Evaluation of the Familial Cancer programme in Western Australia : predictive Genetic Testing for Familial Adenomatous Polyposis and Hereditary Non-Polyposis Colorectal Carcinoma

Aim: To evaluate costs and outcomes of genetic testing for familial colorectal cancer through services provided by Genetic Services of Western Australia (GSWA). Methods: Costs and outcomes of predictive DNA-based testing for inherited colorectal cancers (CRC) were assessed, specifically for familial adenomatous polyposis (FAP) and hereditary non-polyposis CRC (HNPCC) using a decision-analysis model. Costs were assigned according to standards of care in Western Australia (WA). Cancer risks and the efficacy of surveillance on long-term outcomes were derived from the published literature. Results: The cost-effectiveness of genetic testing was compared in first-degree relatives of known mutation carriers who have a 50% risk of carrying the mutated gene (intervention group) to individuals with the same risk but who do not undergo a genetic test (control subjects). Compared with control subjects undergoing the same high-level surveillance and surgery, the FAP and HNPCC intervention groups provided total savings of $ 13,390 and 14,783–15,460 per person (males-females), respectively. HPNCC mutation carriers also gained 1 CRC-free year. Compared to control subjects having only population surveillance, individuals in the FAP intervention group delayed the onset of CRC by 40 years for a net cost of $ 9,042. Individuals in the HNPCC intervention group delayed the onset of CRC by 8 years at a net cost of $ 12,141 for males and $ 12,596 for females. Conclusions: Genetic testing for familial CRC in WA allows targeted surveillance for mutation carriers, which ensures the efficient use of resources and reduces cancer-related morbidity, if clinical recommendations for intervention are adopted.