Background: Increased patient engagement in decision making may mitigate disparities in breast cancer surgical care. Socioeconomically disadvantaged patients disproportionately experience barriers to engagement. Decision aids (DA) increase engagement by providing information, establishing role expectations during the consult, and increasing confidence in surgeon interactions. The objective was to test the effectiveness of a surgical web-based DA in increasing engagement among breast cancer patients in clinics that care for a high proportion of socioeconomically disadvantaged patients. Methods: A stepped wedge trial was conducted with 10 NCI Community Oncology Research Program clinics (Alliance for Clinical Trials in Oncology Research Base, 6/19-12/21). Clinics were randomized to time of transition from usual care (UC) to delivery of a web-based DA. Patients with stage 0-3 breast cancer eligible for surgery provided consent prior to a surgical consult. Socioeconomic disadvantage was assessed with the Area Deprivation Index measured at the zip+4 level and dichotomized. Patient engagement was measured by Patient’s Self-Efficacy in Patient-Physician Interactions (PEPPI-5, follow-up survey) and count of Active Patient Behaviors (Street protocol, audio recorded consult). Intervention effects were tested with linear mixed-effects models, accounting for surgeon and clinic-level clustering, time, and enrollment post-COVID. Heterogeneity of treatment effect by socioeconomic disadvantage was assessed with an interaction term. Results: 573 patients enrolled. 44% (136/309) reviewed the DA. No significant difference in engagement was observed comparing DA and UC for PEPPI-5 (-0.80 [95% CI -2.13, 0.54], p = 0.24) or Active Patient Behaviors (2.52 [CI -4.11, 9.15], p = 0.46). Enrollment post-COVID was associated with increased Active Patient Behaviors (9.59 [CI 1.76, 17.43], p = 0.02) but no change in PEPPI-5 (-1.31 [CI -2.88, 0.26], p = 0.10). No heterogeneity of treatment effect was observed. Conclusions: In this trial conducted in clinics that serve diverse populations, no significant relationship was observed between a web-based DA and patient engagement. Conducting this stepped wedge trial during the pandemic was challenging. Future analyses will explore the impact of COVID on outcomes and effect of the decision aid for patients who reviewed it. UG1 CA189823; AHRQ R01HS025194; https://acknowledgments.alliancefound.org. Clinical trial information: NCT03766009.

*Higher scores indicate higher engagement.