Mapping variation in breast cancer screening: Where to intervene?
Abstract Introduction Mammography screening can reduce breast cancer mortality among women aged 50 years and older. Small geographic areas with lower breast cancer screening uptake may reflect gaps in screening efforts. Our objective was to identify the geographic variations of breast cancer screening uptake among women aged 50-74 years in the Lyon Metropole area, France. Methods We used spatial regression models within a generalized additive framework to determine the clusters of census blocks with significantly lower risk of breast cancer screening uptake. Census block-level data on breast cancer screening participation rates were calculated for women aged 50-74 years who did a mammography between 2015-2016 after being invited with a letter by the cancer screening organization. Using smoothed risk maps adjusting for covariates, we estimated the impact of the spatial distribution of deprivation index, part of opportunistic screening on breast cancer screening participation. Results Between 2015 and 2016, the participation rate of organized breast cancer screening was 49.9%. As hypothesized, women living in highly deprived census blocks had lower participation rates compared to less deprived. However, women living in rural areas with fewer certified mammography services than in urban areas had the highest participation rate. Spatial analyses identified four clusters, one located in an urban area and three in suburban areas. Conclusions Our analysis indicates that depending on the location of the cluster, the influence came from different variables. Knowing the impact of site-specific risk factors is important for implementing an appropriate prevention intervention. Key messages Spatial analysis for cancer screening can help to improve health initiatives. This study contributes to a better understanding of the cluster-specific factors that explain geographic disparities.