In clinical practice settings rather than ideal clinical trial conditions, gene expression profile (GEP) testing in early stage breast cancer appears to be less cost-effective than previously reported (J Clin Oncol 2017;35:doi:10.1200/JCO.2017.74.5034). The findings “underscore the importance of considering real-world implementation when assessing … new technology,” according to the authors.

Researchers at Georgetown University and Kaiser Permanente Northern California (KPNC) examined the cost-effectiveness of Oncotype DX, the most commonly used GEP in the U.S. to support treatment decisions for patients with early stage, node-negative, estrogen receptor-positive, human epidermal growth factor 2-negative cancers. Prior economic analyses evaluating “hypothetical cohorts under ideal conditions” had concluded that this test had low costs relative to its benefits, according to the researchers.

The investigators developed a simulation model to assess 25-year societal incremental costs and quality adjusted life years (QALY) associated with Oncotype DX testing from 2005 to 2012 versus usual care from 2000 to 2004 before GEP began. The researchers used national cancer statistics for incidence rates and based Oncotype DX testing and chemotherapy use rates from KPNC data.

After running 100 million simulations to account for uncertainty, inflation, test accuracy, the benefit of assurance versus worry, and other variables, the authors concluded that 24% of GEP-eligible patients had this test, with younger women and those with early stages of disease more likely to use it. Overall, 30% of women received chemotherapy, but women younger than age 50 who had GEP had lower chemotherapy rates than similar-aged women who did not undergo GEP. Conversely, women older than age 50 who had GEP had higher chemotherapy rates than those who did not undergo GEP.

The cost-effectiveness ratio for GEP testing versus usual care was $188,125 per QALY. With perfect test accuracy, the cost-effectiveness ratio dropped to $28,947 per QALY, and under ideal conditions assuming 100% adherence to test-guided therapy, it was $39,496 per QALY.