Remote Monitoring and Self-Efficacy: Implications for Breast Cancer Survivorship Outcomes.

To examine whether self-efficacy in managing symptoms is associated with symptom burden and adjuvant endocrine therapy (AET) adherence among women with early-stage breast cancer and whether self-efficacy modifies the effects of a remote monitoring intervention. Post hoc analysis of a randomized trial evaluating app-based remote monitoring of self-reported symptoms and adherence for women prescribed AET. Participants were randomly assigned to enhanced usual care (EUC), app only (weekly remote monitoring), or app plus feedback (with weekly tailored supportive text messages). Outcomes included 12-month symptom burden (Functional Assessment of Cancer Therapy-Endocrine Subscale [FACT-ES]) and adherence (≥ 80% of expected doses recorded using a connected pillbox). Multivariable regression evaluated associations of the PROMIS (Patient-Reported Outcomes Measurement Information System) Self-Efficacy for Managing Symptoms T score with symptom burden and adherence as well as differential intervention effects by self-efficacy level. Among 264 participants (mean age, 58.5 years; 64% White, 32% Black), mean (SD) baseline self-efficacy exceeded the normative mean of 50 (54.2 [9.9]). Higher self-efficacy was associated with lower symptom burden (eg, higher FACT-ES score: 0.6; 95% CI, 0.3-0.8) and greater odds of adherence (OR, 1.1; 95% CI, 1.0-1.1). Adherence benefits were greater at lower self-efficacy levels (eg, at a score of 30, 52.7% were adherent in app + feedback vs 17.8% in EUC; +34.9 percentage points; 95% CI, 1.0-68.9; P  = .04), with effects diminishing and becoming nonsignificant at higher self-efficacy levels. Without additional support, breast cancer survivors with low self-efficacy had poorer symptom control and lower adherence. Remote symptom monitoring with tailored messaging was most effective among women with lower self-efficacy levels, highlighting the need for screening and targeted interventions for patients most likely to benefit.