Factors influencing attendance of peer support interventions for Black women with endometrial cancer in the Social Interventions for Support During Treatment for Endometrial Cancer and Recurrence (SISTER) study.

Abstract

338 Background: U.S. Black women with endometrial cancer (EC) face the greatest mortality disparity in gynecologic oncology. Supportive care programs must therefore be designed to reach this population. The SISTER Study was a hybrid effectiveness-implementation trial of two six-month long peer support interventions (one-on-one and group-based) aimed at improving treatment completion and reducing social isolation for Black women with high-risk EC. We aim to describe factors influencing the attendance of these interventions. Methods: We conducted a mixed-methods process evaluation of the SISTER Study interventions between September 2021 and September 2025. We interviewed participants at 6-months after enrollment (N=45) using questions addressing domains of the Consolidated Framework for Implementation Research (CFIR). Peer Supporters documented intervention attendance and we collected participant characteristics from surveys completed prior to randomization. For quantitative data, descriptive and bivariate analyses were conducted. Qualitative data were analyzed using CFIR and directed content analysis. Results: Of participants randomized to peer support arms (N=181), 70% (n=127) attended at least one intervention session. Participants reported several factors influencing attendance. Facilitators of attendance included: flexible scheduling of one-on-one support, ease of virtual attendance, the potential to help other EC patients, and relationship-building with peer supporters and other attendees. Barriers reported were inflexibility of group scheduling, technological challenges, and additional barriers rooted in symptom burden. For example, fatigue and brain-fog resulted in forgetting or sleeping through appointments, and resting was sometimes prioritized over attending. In quantitative analysis, higher comorbidity scores on the modified Charlson Comorbidity Index correlated with reduced attendance (RR per one-point increase=0.90; 95%CI: 0.84-0.97), as did enrolling from a hospital based in the Southeast compared to the Midatlantic region (RR=0.76; 95%CI 0.61-0.95). Conclusions: One-on-one and group peer support interventions were highly attended by a cohort of Black women with high-risk EC. Our findings reveal several logistical and relational strengths of the SISTER interventions for reaching this population. Thoughtfully replicating these strengths and addressing identified barriers to attendance can enhance the quality of future supportive care programs for this high-risk population. Clinical trial information: NCT04930159 .