ASPO Abstracts
Mediation Analysis of Intervention Effects in a Randomized Controlled Trial to Improve Utilization of Cancer Genetic Risk Assessment among High-risk Cancer Survivors
Category: Behavioral Science & Health Communication
Conference Year: 2023
Abstract Body:
Purpose: In the Genetic Risk Assessment for Cancer Education and Empowerment Project, a theory-guided, multi-component Tailored Counseling and Navigation (TCN) intervention increased cancer genetic risk assessment (CGRA) uptake among female cancer survivors at increased risk of hereditary breast and ovarian cancer (HBOC). To understand the mechanisms underlying the intervention effects, we examined whether TCN exerted effects on CGRA uptake through hypothesized theoretical mediators. Methods: Geographically and ethnically diverse breast and ovarian cancer survivors were recruited from three statewide cancer registries. Women who were assigned to TCN (n = 212) received an initial phone-based psychoeducation that used principles of motivational interviewing, a follow-up tailored letter, and a navigation phone call. No intervention was delivered to the Usual Care arm (n = 213). All participants completed surveys that assessed theoretical mediators at baseline and 1-month post-intervention. CGRA uptake was assessed at 6 months and verified through medical records. Generalized Structural Equation Modeling was used for mediation analysis. Results: Compared to Usual Care, TCN directly increased perceived susceptibility (βDE = 0.25, 95% confidence interval (CI) = 0.076-0.43), self-efficacy (βDE = 0.21, 95% CI = 0.013-0.42), and knowledge of HBOC (βDE = 0.19, 95% CI = 0.018-0.36). Increased perceived susceptibility and self-efficacy improved CGRA uptake through strengthened behavioral intention; their indirect effects were βIE = 0.034, 95% CI = 0.0043-0.11 and βIE = 0.043, 95% CI = 0.0014-0.14, respectively. Increased knowledge of HBOC improved response efficacy beliefs about CGRA (βDE = 0.21, 95% CI = 0.066-0.35), which in turn strengthened intentions and CGRA uptake. Conclusions: These findings supported the hypothesized mediation, indicating that TCN effectively improved the key theoretical intervention targets. Risk communication interventions should stress the increased risk of having a pathogenic variant and the potential benefits of genetic testing and bolster efficacy beliefs and motivation by helping remove barriers to CGRA.
Keywords: remote behavioral intervention, cancer genetic risk assessment, hereditary cancer