Cost effectiveness of the Oncotype DX DCIS Score for guiding treatment of patients with ductal carcinoma in situ

Purpose: The Oncotype DX DCIS Score short form (DCIS Score) estimates the risk of an ipsilateral breast event (IBE) in patients with ductal carcinoma in situ (DCIS) treated with breast-conserving surgery without adjuvant radiation therapy (RT). We determined the cost effectiveness of strategies using this test. Materials and Methods: We developed a Markov model simulating 10-year outcomes for 60-year-old women eligible for the Eastern Cooperative Oncology Group E5194 study (cohort 1: low/intermediate-grade DCIS, ≤ 2.5 cm; cohort 2: high-grade DCIS, ≤ 1 cm) with each of five strategies: (1) no testing, no RT; (2) no testing, RT only for cohort 2; (3) no RT for low-grade DCIS, test for intermediate- and high-grade DCIS, RT for intermediate- or high-risk scores; (4) test all, RT for intermediate- or high-risk scores; and (5) no testing, RT for all. We used utilities and costs extracted from the literature and Medicare claims to determine incremental cost-effectiveness ratios and examined the number of women needed to irradiate per IBE prevented. Results: No strategy using the DCIS Score was cost effective. The most cost-effective strategy (RT for none or RT for all) was sensitive to small differences between the utilities of receiving or not receiving RT and remaining without recurrence. The numbers needed to irradiate per IBE prevented were 10.5, 9.1, 7.5, and 13.1 for strategies 2 to 5, respectively, relative to strategy 1. Conclusion: Strategies using the DCIS Score lowered the proportion of women undergoing RT per IBE prevented. However, no strategy incorporating the DCIS Score was cost effective. The cost effectiveness of RT was exquisitely utility sensitive, highlighting the importance of engaging patient preferences in this decision. Physicians should discuss trade-offs associated with omitting or adding adjuvant RT with each patient to maximize quality-of-life outcomes.