Impact of the 92-gene assay on cost of diagnosis of tumor type in metastatic cancer of uncertain origin.
e15104 Background: Molecular classification of tumors has been incorporated into clinical algorithms for patients with metastatic cancers of uncertain origin. This study is a comprehensive cost analysis—characterizing standard of care for metastatic disease, cost implications of correct vs incorrect diagnosis, and cost effectiveness of implementing molecular classification into the diagnostic paradigm. Methods: A deterministic model was developed to project the cost and effectiveness of standard care for metastatic tumors of uncertain origin, compared with incorporating use of the 92-gene assay at 3 points: before immunohistochemical (IHC) analysis, or after 1, or 2 sets of IHC stains. For each strategy, total and incremental costs, life-years (LYs), quality-adjusted life years (QALYs), and incremental cost effectiveness ratios (ICERs) were projected, as well as the % of patients treated correctly vs incorrectly. Model inputs and costs were based on published literature, analyses of the SEER database, the Physicians’ Fee and Coding Guide 2012, and interviews with disease experts. Sensitivity analyses were performed on key inputs. Results: When standard care was compared with each 92-gene assay strategy, costs increased between $4,804 and $6,038 and QA-survival by 1.03-1.15 months. Using the 92-gene assay after 1 set of IHC stains was the most cost effective strategy ($50,273/QALY). Overall, the 92-gene assay increased the % of patients treated correctly and decreased the % of patients treated with empiric therapy compared with standard care. When compared with incorrect treatment, correct treatment provided an additional 5.4 QA-months of survival. Sensitivity analyses identified that costs of empiric treatment, the 92-gene assay, and lung cancer treatment had the greatest effect on outcomes. At a societal willingness-to-pay (WTP) threshold of $100,000, the 92-gene assay was cost effective 94% to 99% of the time. Conclusions: Use of the 92-gene assay is considered cost effective using current societal WTP thresholds, represents an efficient use of economic resources that improves patients' survival and quality of life, and could contribute to standardization of the costs of diagnosis.