title: Cost-utility of the 21-gene recurrence score assay in node-negative and node-positive breast cancer.
abstract: The 21-gene recurrence score (Oncotype DX: RS) appears to augment clinico-pathologic prognostication and is predictive of adjuvant chemotherapy benefit in node-negative (N-) and node-positive (N+), endocrine-sensitive breast cancer. RS is a costly assay that is associated with good 'value for money' in N- disease, while economic evaluations in N+ disease based on most recent data have not been conducted. We examined the cost-utility (CU) of a RS-guided adjuvant strategy, compared to current practice without RS in N- and N+, endocrine-sensitive, breast cancer from a Canadian health care system perspective. A generic state-transition model was developed to compute cumulative costs and quality-adjusted life years (QALYs) over a 25-year horizon. Patient outcomes with and without chemotherapy in RS-untested cohorts and in those with low, intermediate and high RS were examined based on the reported prognostic and predictive impact of RS in N- and N+ disease. Chemotherapy utilization (current vs. RS-guided), unit costs and utilities were derived from a Nova Scotia Canadian population-based cohort, local unit costs and the literature. Costs and outcomes were discounted at 3% annually, and costs were reported in 2011 Canadian dollars ($). Probabilistic and one-way sensitivity analyses were conducted for key model parameters. Compared to a non-RS-guided strategy, RS-guided adjuvant therapy was associated with $2,585 and $864 incremental costs, 0.27 and 0.06 QALY gains, and resultant CUs of $9,591 and $14,844 per QALY gained for N- and N+ disease, respectively. CU estimates were robust to key model parameters, and were most sensitive to chemo utilization proportions. RS-guided adjuvant therapy appears to be a cost-effective strategy in both N- and N+, endocrine-sensitive breast cancer with resultant CU ratios well below commonly quoted thresholds.
authors.affiliation: Department of Medicine, Dalhousie University, 454 Bethune Building. 1276 South Park Street, Halifax NS, B3H 2Y9, Canada.
authors.forename: Nathan W D
authors.initials: NW
authors.lastname: Lamond
authors.forename: Chris
authors.initials: C
authors.lastname: Skedgel
authors.forename: Daniel
authors.initials: D
authors.lastname: Rayson
authors.forename: Lynn
authors.initials: L
authors.lastname: Lethbridge
authors.forename: Tallal
authors.initials: T
authors.lastname: Younis
mesh_terms: D001943:Breast Neoplasms / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology; D003362:Cost-Benefit Analysis; D005260:Female; D020869:Gene Expression Profiling / Q000191:economics* / Q000379:methods*; D006801:Humans; D008390:Markov Chains; D009367:Neoplasm Staging; D019057:Quality-Adjusted Life Years