UCSF

Colorectal cancer (CRC) remains a significant public health problem worldwide, with incidence and mortality increasing, especially in low- and middle-income countries. Effective screening programs are crucial for early detection and to reduce the burden of this disease. In Mexico, where there is currently no national CRC screening program in place, CRC mortality has increased significantly over the last two decades. In contrast, in the United States (US) and specifically in California, the state with the highest number of Hispanic and Latino populations in the US, CRC screening has been available for decades, and an overall decline in incidence and mortality has been observed in the past four decades. Considering these trends and stages in the implementation of colorectal cancer screening programs in both contexts, the overall objective of this dissertation was to conduct formative work to understand and improve colorectal cancer screening in both contexts. In Mexico, it focuses on studying the feasibility of integrating fecal immunochemical test-based screening into an existing door-to-door vaccination program in Mexico City (Chapter 1), and in an integrated healthcare system in Nuevo Leon (Chapter 2). In the US, specifically in California, where there have been decades of experience, it focuses on assessing the ecological association between CRC screening and late-stage disease at diagnosis and identifying zones where efforts to increase screening and to understand and address barriers are needed to improve CRC outcomes (Chapter 3).