A Nationwide Exploration of Social Inequalities in Cancer Mortality Amidst the COVID-19 Pandemic in Belgium

Background: The COVID-19 pandemic disrupted global health systems, impacting cancer care and potentially increasing cancer mortality, especially among socioeconomically disadvantaged individuals. We aimed to assess changes in cancer mortality from March 1 to December 31, 2020 relative to the same period in 2019, and to examine potential shifts in cancer mortality's social disparities during the same time frame.

Methods: We used nationwide individually linked cancer mortality data from the Belgian National Register, the Census 2011, and the tax register. Analyses were stratified by age group (45-59 years, 60-74 years, 75+ years) and sex across all cancer types, including breast, colorectal, lung, pancreatic, and prostate. Direct age-standardized mortality rates were calculated in 2019 and 2020 to calculate absolute and relative changes in cancer mortality by social indicators. Relative inequalities in cancer mortality by social groups were calculated for both time frames using Poisson regression. Sensitivity analysis considered any mention of specified cancer groups on the Belgian death certificate.

Results: For both overall and site-specific cancers, our study found decreases in cancer mortality during the pandemic's early stages, particularly among individuals aged 75 and older. These changes did not significantly alter established socioeconomic patterns in cancer mortality.

Conclusions: Reductions in reported cancer deaths in 2020 may reflect COVID-19 prioritization in cause-of-death coding and its role as a competing risk, rather than true declines. Persistent educational disparities emphasize the need for continued policy and healthcare collaboration, with future research focused on the pandemic's long-term effects on cancer mortality and social inequalities.