OBJECTIVES

Genetic testing for a germline BRCA mutation in women with HER2-negative metastatic breast cancer (MBC) can guide targeted treatment with PARP inhibitors (e.g. olaparib) and inform cancer prevention strategies (e.g., risk-reducing surgery) for family members of women who test positive. Unlike BRCA testing in localised breast cancer, the cost-effectiveness of genetic testing in MBC is unknown. This study aimed to evaluate the cost-effectiveness of BRCA testing in women with MBC to guide olaparib treatment.

METHODS

A cost-effectiveness analysis was conducted using a cohort Markov model from an Australian health-payer perspective. Two scenarios were evaluated: 1) BRCA testing of women with MBC followed by olaparib if the test is positive; and 2) BRCA testing of women with MBC followed by olaparib and cascade testing of 1^st and 2^nd degree family members if the test is positive. Olaparib effectiveness was based on the OlympiAD trial, other parameters were systematically identified from the literature to populate the model. Uncertainty was characterised using probabilistic sensitivity analysis.

RESULTS

Compared with no testing and standard chemotherapy, Scenario1 resulted in 0.04 QALYs gained at an incremental cost of AU$11,607 whereas Scenario2 resulted in 0.12 QALYs gained at an incremental cost of AU$12,575. At a willingness-to-pay threshold of AU$100,000/QALY and at the listed price of olaparib, none of the scenarios were cost-effective. Probability of being cost-effective was 0% and 40% for Scenario1 and Scenario2, respectively. If olaparib price is reduced by at least 65%, the two scenarios would become cost-effective, with Scenario2 offering an additional AU$1,100 in monetary benefits over Scenario1.

CONCLUSIONS

Genetic testing for BRCA germline mutation to guide olaparib treatment in women with MBC is not cost-effective unless the price of olaparib is significantly reduced. Extending BRCA testing to cover family members of mutation carriers would provide additional benefits compared with testing affected women only.