Cost-effectiveness of endocrine therapy or radiation treatment alone or in combination for standard- and good-risk DCIS

Introduction: Ductal carcinoma in situ (DCIS) accounts for 20% of breast cancer cases in the United States and is potentially overtreated leading to high expenditures and low-value care. We conducted a first-of-its-kind cost-effectiveness analysis evaluating all available treatment strategies for both standard- and good-risk DCIS. Methods: We created a Markov model with six different post-operative treatment strategies: observation, tamoxifen (TAM), aromatase inhibitor (AI), radiation treatment (RT), RT + TAM, and RT + AI. Baseline recurrence rates were modeled using NSABP B17 for standard-risk DCIS and RTOG 9804 for good-risk DCIS. Relative risk reductions and adverse event rates for each treatment strategy were derived from meta-analyses of large randomized trials. Both hypofractionated and conventionally fractionated RT regimens were separately used as model inputs. A Medicare payer perspective was utilized with a lifetime horizon for two cohorts of women, aged 40 and 60 years old. The willingness-to-pay threshold was assumed at $100,000/quality-adjusted life-year (QALY). Deterministic and probabilistic sensitivity analyses (PSA) evaluated the robustness of base-case results. Results: TAM or AI alone, for women 40 or 60 years of age, respectively, led to lower costs and lower QALYs compared to observation, due to disutility of treatment symptoms for five years. RT alone (either hypofractionated or conventionally fractionated) was cost-effective compared to observation for standard-risk but not good-risk patients, as shown in the Table. In all scenarios, RT + TAM and RT + AI strategies were dominated; that is, these strategies had higher costs and lower QALYs than a combination of alternative strategies. Results were most sensitive to cost and utility of RT, such that either decreased cost or increased utility rendered RT alone cost-effective for younger, good-risk patients. PSA results indicated that the probability of hypofractionated RT being cost-effective was 82.2% for age 60, standard-risk patients, but only 3.9% for age 60, good-risk patients (Table). Conclusion: RT in combination with TAM/AI, although the most commonly recommended treatment for DCIS, represents low-value care. Similarly, AI or TAM alone is often recommended for patients with good-risk DCIS, yet neither appears to be an optimal treatment strategy. Given the current emphasis on value-based practice, our results suggest that the medical community should promote RT alone for standard-risk DCIS and observation or RT alone for good-risk DCIS based upon patient age and preference for RT. Citation Format: Apar Gupta, Bruce G Haffty, Sachin R Jhawar, Mutlay Sayan, Zeinab Abou Yehia, James B Yu, Shiyi Wang. Cost-effectiveness of endocrine therapy or radiation treatment alone or in combination for standard- and good-risk DCIS [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P6-16-02.