The potential economic impact of the 21-gene recurrence score: Guided chemotherapy in a population-based cohort with node-negative and node-positive early-stage breast cancer.

Abstract

201 Background: The 21-gene recurrence score (Oncotype DX: RS) appears to augment clinical-pathological prognostication and predicts adjuvant chemotherapy (chemo) benefits in patients with node-negative (N-) and node-positive (N+) hormone-receptor positive early-stage breast cancer. Economic analyses suggest that RS-guided chemo is a cost-effective strategy in N- breast cancer, but no evaluations were reported for N+ disease based on pre RS chemo utilization in clinical practice. We examined the cost-utility (CU) of a RS-guided chemo strategy, compared to current practice without RS in a population based cohort, in N- and N+ early-stage breast cancer. Methods: A generic state-transition model was developed to compute cumulative costs and quality-adjusted life years (QALY) over a 25-year horizon for patients with hormone-receptor positive early-stage breast cancer considered for chemo. We examined outcomes with and without chemo in RS-untested cohorts and in those with low, intermediate and high RS based on the reported prognostic and predictive impact of the RS. Chemo utilizations (current vs RS-guided), costs and utilities were derived from a Nova Scotia population based cohort, local resources and the literature. Sensitivity analyses were conducted for key model assumptions/parameters. Results: RS-guided chemo strategy is associated with incremental costs and QALY gains compared to chemo with no RS testing in both N- and N+ patients. The resultant CU ratios are $17,141/QALY and $5,772/QALY for N- and N+ disease, respectively. These CU ratios are well below commonly quoted thresholds and were most sensitive to RS-distribution, upfront chemo costs, chemo utilization rates and relative benefits of chemo in various RS-strata. Conclusions: RS-guided chemo in a population based cohort appears to be a cost-effective strategy, compared to chemo with no RS testing, in N- and N+ early-stage breast cancer.