DO ADVANCES IN BREAST CANCER TREATMENT RENDER SCREENING MAMMOGRAPHY NOT COST-EFFECTIVE FOR AVERAGE-RISK WOMEN?

OBJECTIVES: Researchers have postulated that screening mammography could become less effective in reducing cancer mortalities as breast cancer (BC) treatment improves over time. We evaluated the association between treatment advances and the cost-effectiveness of screening mammography for women at average-risk for BC. METHODS: Our microsimulation model includes "no screening" plus 6 other strategies at three initiation (40/45/50) and two cessation ages (75/80). We captured treatment advances by modeling a hypothetical treatment with the same hazard reduction and costs as trastuzumab but would benefit 50% (or 100%) of BC patients, instead of only HER2+ patients. We obtained clinical parameters from the literature or statistical modeling and cost parameters from Medicare fee schedule and SEER-Medicare. Deterministic CEA was based on simulating a birth cohort of 500,000 women and probabilistic CEA from 100 repetitions of the simulation, each with a cohort of 100,000 women. RESULTS: The most cost-effective screening strategy in the base case scenario was a hybrid strategy that started screening at 45 and switched to biennial between 55 and 75, yielding ICER $69,235/QALY. The ICER of the same strategy increased to $70,612/ QALY and $71,162/QALY in the scenario in which the new treatment benefited 50% and 100% of patients, respectively. At $50,000/QALY willingness-to-pay, the probability that this hybrid strategy yielded the highest net benefit was 30% at base case, and reduced to 28% and 23% in the 50% and 100% new treatment scenario, respectively. At $100,000/QALY, the probability that the above hybrid strategy had the highest net benefit stayed around 37% for all three scenarios. CONCLUSIONS: Treatment advances reduce the cost-effectiveness of screening mammography, especially in countries with lower CE threshold. For countries with a higher CE threshold, a new treatment would have to be substantially better than trastuzumab and benefit a large proportion of patients to render screening mammography not cost-effective.