Purpose: New evidence from two recently-published studies was applied to reevaluate the cost-effectiveness of the 21-gene Recurrence Score (RS) assay (Oncotype DX) in the context of multifactorial decision making to guide the use of chemotherapy for node-negative, estrogen receptor–positive breast cancer in the United States from the societal and healthcare system perspectives.
Methods: In order to cross-classify hypothetical patients by clinicopathologic characteristics according to the Adjuvant! decision aid and 21-gene RS risk groups, we developed a probabilistic decision-analytic model to generate estimates of long-term costs, survival, and quality-adjusted survival for the RS-guided and non–RS-guided strategies. In addition to costs for the 21-gene assay, we assigned attributable costs for chemotherapy, hormonal therapy, monitoring for disease recurrence, and distant recurrence. For the societal perspective, we also considered incremental patient time costs. Costs and survival were discounted at 3% annually.
Results: With the RS-guided strategy, 40.4% of patients were expected to receive chemotherapy relative to 47.3% in the non–RS-guided strategy. Estimated rates of recurrence at 10 years were 6.8% with the RS-guided strategy and 8.9% with the non-RS guided strategy. Targeted use of chemotherapy in the RS-guided strategy was expected to increase survival by 0.19 years (95% CI, 0.09 to 0.32) and 0.16 QALYs (95% CI, 0.08 to 0.28). Lifetime direct medical costs were expected to be $2692 (95% CI, 1546 to 3821) higher with the RS-guided strategy. The incremental cost-effectiveness ratios (ICERs) were $14,059 per life-year saved (95% CI, $6840-$28,912) and $16,677 per QALY (95% CI, $7613-$37,219). When incorporating lower patient time costs of $950 per patient, the ICERs were $9095 per life-year saved (95% CI, dominant-$23,397) and $10,788 per QALY (95% CI, $6840-$30,265). In probabilistic sensitivity analysis, more than 99% of the ICERs were less than $50,000 per life-year saved and per QALY. Numerous sensitivity analyses were conducted to evaluate the impact of varying assumptions regarding the use of chemotherapy in lower-risk and higher-risk women and varying model parameters pertaining to costs, health utilities, and disease recurrence. Across sensitivity analyses, ICERs remained below $22,000 per QALY.
Conclusions: Our updated cost-effectiveness estimates are supportive of the economic value of the 21-gene RS assay in the setting of node-negative, estrogen receptor–positive breast cancer.