Exploring tradeoffs in approaches to providing and promoting colorectal cancer screening in low-income, medically underserved populations using causal loop diagramming

Public health initiatives such as the Colorectal Cancer Control Program (CRCCP) aim to improve colorectal cancer (CRC) screening in low-income, medically underserved populations, but need to decide how to invest limited resources for the greatest gains. We wanted to understand and document the tradeoffs in different approaches to providing screenings directly (e.g., via stool testing or colonoscopy) and to promoting CRC screening through the implementation of evidence-based interventions (EBIs). We identified peer-reviewed papers that evaluated CRCCP-funded initiatives seeking to promote and/or provide screening. Through inductive coding we identified excerpts from these papers that addressed advantages or disadvantages to approaches to improving CRC screening. After identifying high-level themes in the data, we developed integrative narrative summaries and Causal Loop Diagrams (CLDs) by theme using best practices from systems thinking. From the 38 papers identified, we coded 457 excerpts related to tradeoffs and generated five CLDs based on the following high-level themes: 1) navigating system dynamics in selecting and implementing EBIs for CRC screening, 2) ensuring long-term sustainability of EBIs for CRC screening, 3) cost drivers and cost-effectiveness of EBI implementation, 4) cost considerations of stool-based testing versus colonoscopies, and 5) factors influencing CRC screening and follow-up. Important considerations across themes related to time-limited funding cycles, evolving characteristics of the population needing to be screened, and the impact of early investment in infrastructure and capacity building. CLDs are an effective tool for visualizing tradeoffs, understanding how to optimize resources, and leveraging the greatest impact from different interventions to support CRC screening over time.