The impact of gene expression profile testing on confidence in chemotherapy decisions and prognostic expectations

Purpose: Little is known about whether gene expression profile (GEP) testing and specific recurrence scores (e.g., medium risk) improve women’s confidence in their chemotherapy decision or perceived recurrence risk. We evaluate the relationship between these outcomes and GEP testing. Methods: We surveyed women eligible for GEP testing (stage I or II, Gr1-2, ER+, HER2−) identified through the Surveillance, Epidemiology, and End Results (SEER) Registry of Washington or Kaiser Permanente Northern California from 2012 to 2016, approximately 0–4 years from diagnosis (N = 904, RR = 45.4%). Confidence in chemotherapy was measured as confident (Very, completely) versus Not Confident (Somewhat, A little, Not At All); perceived risk recurrence was recorded numerically (0–100%). Women reported their GEP test receipt (Yes, No, Unknown) and risk recurrence score (High, Intermediate, Low, Unknown). In our analytic sample (N = 833), we propensity score weighted the three test receipt cohorts and used propensity weighted multivariable regressions to examine associations between the outcomes and the three test receipt cohorts, with receipt stratified by score. Results: 29.5% reported an unknown GEP test receipt; 86% being confident. Compared to no test receipt, an intermediate score (aOR 0.34; 95% CI 0.20–0.58), unknown score (aOR 0.09; 95% CI 0.05–0.18), and unknown test receipt (aOR 0.37; 95% CI 0.24–0.57) were less likely to report confidence. Most women greatly overestimated their recurrence risk regardless of their test receipt or score. Conclusions: GEP testing was not associated with greater confidence in chemotherapy decisions. Better communication about GEP testing and the implications for recurrence risk may improve women’s decisional confidence.