Demographic factors associated with differential uptake and outcomes of breast cancer screening in English regions: 2007-2020.

[OBJECTIVE] Breast cancer is the most prevalent cancer among UK women. Screening aims to detect cancer early, improving treatment options and survival. However, participation varies across England with lower participation and cancer detection rates in London than other regions. We postulate that demographic factors (age, ethnicity, deprivation, and migration) might explain some regional differences.

[METHODS] An ecological analysis of aggregated data compared English regions (April 2007 - March 2020). Primary outcomes were breast cancer mortality, coverage rate, and rate of screen-detected invasive cancers. Linear regression analyses compared outcomes between London and other English regions, adjusting for age, ethnicity, deprivation, and migration.

[RESULTS] Data included 104 observations aggregated from 26,202,645 screenings, of which 11.9% were in London. Coverage was lower in London (67.8%) than other English regions (73.6% - 79.8%). London had significantly lower rates of screen-detected invasive cancers (mean = 6.2 per 1000, SD = 0.2) compared to six of seven regions (ranging from 6.3 to 6.9 per 1000) and lower breast cancer mortality rate (mean = 31.7, SD = 0.8) than four regions (ranging from 33.4 to 36.1). Differences in coverage were attenuated and non-significant after adjustment for demographic factors.

[CONCLUSION] Regional differences in screen participation are associated with demographic factors, but breast cancer outcomes in London are not worse than the rest of England. Targeted interventions to improve screening accessibility for underserved communities could reduce inequalities. We describe challenges associated with combining several sources of information when performing our analyses and further research using individual-level data is recommended to confirm results and explore additional predictors.

[ADVANCES IN KNOWLEDGE] This national ecological analysis demonstrates that lower breast screening coverage and invasive cancer detection rates in London are associated with demographic factors, particularly ethnicity, deprivation and migration. Despite poorer participation, breast cancer mortality in London is not worse than in other English regions. The findings emphasise the importance of demographic factors in breast screening outcomes and improved data linkage to address regional inequalities in breast cancer screening and outcomes.