The average QALYs gained were 9.20 with tamoxifen, 9.28 with testing and tamoxifen for heterozygous patients, 9.35 with testing and anastrozole for heterozygous patients, and 9.36 with anastrozole. The average cost per patient was £6,816 with tamoxifen, £7,234 with testing and tamoxifen, £8,088 with testing and anastrozole, and £10,169 with anastrozole.
Compared with tamoxifen, testing and tamoxifen had an incremental cost-utility ratio (ICUR) of £4,774 per QALY gained. Compared with testing and tamoxifen, testing and anastrozole had an ICUR of £13,864 per QALY gained. Compared with testing and anastrozole, anastrozole had an ICUR of £177,096 per QALY gained.
Assuming a generic price for anastrozole, the average cost per patient was £7,063 with testing and tamoxifen, £7,001 with testing and anastrozole, and £6,777 with anastrozole. Tamoxifen, testing and tamoxifen, and testing and anastrozole were dominated by anastrozole, as anastrozole was less costly and more effective.
The probabilistic sensitivity analysis showed that at a willingness-to-pay threshold of £20,000 to £30,000 per QALY gained, testing and anastrozole was cost-effective in between 50% and 60% of simulations, assuming the patent price for anastrozole, and anastrozole was cost-effective in approximately 60% of simulations, assuming its generic price. The expected value of perfect information analysis suggested that further research was feasible, as the value of the research was likely to exceed its cost.