Spatial analysis of colorectal cancer outcomes: investigating the impact of place-specific factors using causal inference methods for spatial data.

Background: Disparities in health outcomes across regions may arise from place-specific factors, encompassing both contextual elements such as healthcare accessibility and compositional factors tied to the unique population characteristics. This study seeks to investigate the impact of various place-specific factors on late-stage incidence and mortality rates within Norwegian municipalities.

Method: Municipality-level data on colorectal cancer (CRC) late-stage diagnosis and mortality rates were acquired from the Cancer Registry of Norway and the Norwegian Cause of Death Registry. Screening utilization rates were obtained from the Norwegian Patient Registry. To explore the region-level effects of place-specific factors on CRC outcomes, a causal inference method for spatial data-neighborhood adjustment method via spatial smoothing (NA approach)-was employed.

Results: The findings indicate that a one-unit increase in screening rates (or a 1% rise in screening uptake) corresponds to a 2.9% decrease in late-stage incidence, with a 95% credible interval ranging from -0.055 to -0.003. However, no significant relationship between screening rates and mortality rates was observed.

Conclusion: This study underscores the importance of maximizing the utilization of screening services to prevent advance-stage diagnosis. Moreover, the research underscores the significance of improving access to screening services, particularly in rural and medically underserved areas.