The Challenges of Enrollment and Retention: A Systematic Review of Psychosocial Behavioral Interventions for Patients With Cancer and Their Family Caregivers

Context: Psychosocial behavioral interventions (PBIs) that target patients with cancer and their caregivers face challenges in participant enrollment and retention. Objectives: 1) Describe characteristics of the patient-caregiver PBI studies; 2) examine participant enrollment and retention rates; 3) identify factors influencing participant enrollment and retention rates; and 4) explore the strategies to promote enrollment and retention rates. Methods: We identified randomized controlled trials that tested PBIs among adult patients with cancer and caregivers in five electronic databases. We conducted narrative and quantitative analyses to synthesize our findings. Results: Among 55 qualified studies reviewed, most tested the efficacy of PBIs (n = 42) and used two study arms (n = 48). In-person meeting was the most common PBI delivery mode. The primary outcomes included quality of life, physical health, and symptoms. The average of enrollment rates of patient-caregiver dyads was 33% across studies (range 8%–100%; median = 23%). The average retention rate at the end of follow-ups was 69% (range 16%–100%; median = 70%). The number of study arms, recruitment method, type of patient-caregiver relationship, and intervention duration influenced enrollment rates. Study design (efficacy vs. pilot), follow-up duration, mode of delivery, type of relationship, and intervention duration influenced retention rates. Sixteen studies reported retention strategies, including providing money/gift cards upon study completion and/or after follow-up survey, and excluding patients with advanced cancer. Conclusion: Researchers need to incorporate effective strategies to optimize enrollment and retention in patient-caregiver PBI trials. Researchers need to report detailed study processes and PBI information to improve research transparency and increase consistency.