Cost Effectiveness of Gene Expression Profile Testing in Community Practice

Abstract

Purpose Gene expression profile (GEP) testing can support chemotherapy decision making for patients with early-stage, estrogen receptor-positive, human epidermal growth factor 2-negative breast cancers. This study evaluated the cost effectiveness of one GEP test, Onco type DX (Genomic Health, Redwood City, CA), in community practice with test-eligible patients age 40 to 79 years. Methods A simulation model compared 25-year societal incremental costs and quality-adjusted life-years (QALYs) of community Onco type DX use from 2005 to 2012 versus usual care in the pretesting era (2000 to 2004). Inputs included Onco type DX and chemotherapy data from an integrated health care system and national and published data on Onco type DX accuracy, chemotherapy effectiveness, utilities, survival and recurrence, and Medicare and patient costs. Sensitivity analyses varied individual parameters; results were also estimated for ideal conditions (ie, 100% testing and adherence to test-suggested treatment, perfect test accuracy, considering test effects on reassurance or worry, and lowest costs). Results Twenty-four percent of test-eligible patients had Onco type DX testing. Testing was higher in younger patients and patients with stage I disease ( v stage IIA), and 75.3% and 10.2% of patients with high and low recurrence risk scores received chemotherapy, respectively. The cost-effectiveness ratio for testing ( v usual care) was $188,125 per QALY. Considering test effects on worry versus reassurance decreased the cost-effectiveness ratio to $58,431 per QALY. With perfect test accuracy, the cost-effectiveness ratio was $28,947 per QALY, and under ideal conditions, it was $39,496 per QALY. Conclusion GEP testing is likely to have a high cost-effectiveness ratio on the basis of community practice patterns. However, realistic variations in assumptions about key variables could result in GEP testing having cost-effectiveness ratios in the range of other accepted interventions. The differences in cost-effectiveness ratios on the basis of community versus ideal conditions underscore the importance of considering real-world implementation when assessing the new technology.

Fig 1.

Decision tree and state transitions for patients with stage I or IIA, node-negative, estrogen receptor (ER)–positive, human epidermal growth factor receptor 2 (HER2)–negative breast cancer. (A) Simulation model schema. The model was developed to compare cost effectiveness of community practice with use of Oncotype DX test versus usual care without the test. The community practice arm included observed testing and chemotherapy use in 2005 to 2012. The usual care arm included chemotherapy use patterns in the pre–Oncotype DX era (2000 to 2005). Testing probabilities were conditional on age and stage. The test results affected the probability of chemotherapy use. (B) State transition. All simulated patients were newly diagnosed with ER-positive, HER2-negative, node-negative, stage I or IIA breast cancer. If death from chemotherapy toxicity did not happen at initial treatment, all simulated patients transitioned to the post-treatment state until breast cancer death (if recurrence occurred) or death from other cause (if no recurrence occurred or death from other cause occurred before recurrence). Patients without distant recurrence only died of non–breast cancer causes or chemotherapy toxicity. Patients remain in the same state until the time of a transition event.

Fig 2.

Impact of varying single parameters on the societal cost-effectiveness ratios for Oncotype DX testing in community practice versus usual care without testing among patients with stage I or II, node-negative, estrogen receptor–positive, human epidermal growth factor receptor 2–negative breast cancer. This diagram illustrates the changes in the incremental cost-effectiveness ratio (ICER) for the costs per quality-adjusted life-year (QALY) under various parameter values and alternative assumptions. The solid vertical line represents the base-case ICER result comparing community practice with Oncotype DX testing versus usual care without Oncotype DX. The horizontal bars indicate the change from the base ICER when the one individual parameter is varied. If the bar goes to the right of the base case, it indicates that the alternative value or assumption costs more per QALY than the base case, where bars that go to the left indicate that the alternative value or assumption costs less per QALY than the base case. (*) Test costs were varied from the base case of $3,416 to $2,657 and $4,175. The large difference in cost per QALY when test costs were varied is a result of these effects being magnified by the small incremental QALYs between usual care and community care. (†) The accuracy of the test represents the probability of a test score, conditional on actual distant recurrence. The best test accuracy reflects a greater proportion of women who actually experience recurrence having high-risk scores and a smaller proportion having low-risk scores, and among those who do not experience recurrence, fewer have high-risk scores and more have low-risk scores than in the base case on the basis of observed performance in the original validation study. (‡) The worst testing accuracy was dominated. That is, it resulted in community practice being more costly and producing fewer QALYs than usual care without testing. (§) Net reassurance/worry is based on gaining 0.5 QALY or losing 0.5 QALY over the first 2 years after diagnosis with low- and high-risk recurrence scores, respectively. (‖) One hundred percent adherence to test-guided treatment assumes 100% chemotherapy use among patients with high-risk score on gene expression profile testing, 50% chemotherapy use for intermediate risk, and 0% chemotherapy use for low risk.