Cost Effectiveness Analysis of a Multivariate Index Assay compared to Modified ACOG Criteria and CA-125 in the Triage of Women with Adnexal Masses

Objective: To evaluate the cost-effectiveness of the multivariate index assay (MIA) for use in triaging women with an adnexal mass relative to modified American College of Obstetricians and Gynecologists (mACOG) referral guidelines and CA-125 testing alone. Methods: The MIA triage algorithm was based on qualitative serum testing of five biomarkers: transthyretin, apolipoprotein, A-1, 2-microglobulin, transferrin, and CA-125. An economic analysis was developed to evaluate the clinical and cost implications of adopting MIA in clinical practice versus the mACOG referral guidelines and CA-125 alone, over a lifetime horizon, from the perspective of the public payer. Clinical parameters used to characterize patients' disease status, quality of life, and treatment decisions were estimated using the results of published studies; costs were approximated using reimbursement rates from CMS fee schedules. Model endpoints included overall survival (OS), costs, quality-adjusted life years (QALYs), and incremental cost-effectiveness ratio (ICER). The cost-effectiveness threshold was set to $50,000 per QALY. One-way sensitivity analysis was performed to assess uncertainty of individual parameters included in the analysis. All costs were reported in 2014 US dollars. Results: Use of MIA was cost-effective, resulting in fewer re-operations and pre-treatment CT scans. Overall MIA resulted in an ICER of $35,094/QALY gained. MIA was also cost-saving and QALY-increasing compared to use of CA-125 alone with an ICER of $12,189/QALY gained. One-way sensitivity analysis showed the ICER was most affected by the following parameters: (1) sensitivity of MIA; (2) sensitivity of mACOG; and (3) percentage of patients, not referred to a gynecologic oncologist, who were correctly diagnosed with advanced epithelial ovarian cancer (EOC). Conclusion: Use of MIA is a more cost-effective triage strategy than mACOG or CA-125. It is expected to increase the percentage of women with ovarian cancer that are referred to gynecologic oncologists, which is shown to improve clinical outcomes. Limitations include the use of assumptions when published data was unavailable, and the use of multiple sources for survival data.