The 2020 US cancer screening deficit and the timing of adults' most recent screen: a population-based cross-sectional study.

Objective: In 2020, cancer screenings declined, resulting in a cancer screening deficit. The significance of this deficit, however, has yet to be quantified from a population health perspective. Our study addresses this evidence gap by examining how the pandemic changed the timing of American adults' most recent cancer screen.

Methodology: We obtained population-based, cancer screening data from the Behavioural Risk Factor Surveillance System (BRFSS) (2010, 2012, 2014, 2016, 2018, 2020). Mammograms, pap smears and colonoscopies were each specified as a variable of mutually exclusive categories to indicate the timing since the most recent screening (never, 0-1 years, 1-2 years, 3+ years). Our cross-sectional, quasi-experimental design restricts the sample to adults surveyed in January, February or March. We then leverage a quirk in the BRFSS implementation and consider adults surveyed in the second year of the 2020 survey wave as exposed to the COVID-19 pandemic. Respondents surveyed in January 2020-March 2020 were considered unexposed. To estimate the impact of exposure to the COVID-19 pandemic on the timing of recent cancer screenings, we constructed linear and logistic regression models which control for sociodemographic characteristics associated with screening patterns, and state fixed effects and temporal trend fixed effects to control for confounding.

Results: In 2020, the cancer screening deficit was largely due to a 1 year delay among adults who receive annual screening, as the proportion of adults reporting a cancer screen in the past year declined by a nearly identical proportion of adults reporting their most recent cancer screen 1-2 years ago (3%-4% points). However, the relative change was higher for mammograms and pap smears (17%) than colonoscopies (4%). We also found some evidence that the proportion of women reporting never having completed a mammogram declined in 2020, but the mechanisms for this finding should be further explored with the release of future data.

Conclusion: Our estimates for the pandemic's effect on cancer screening rates are smaller than prior studies. Because we account for temporal trends, we believe prior studies overestimated the effect of the pandemic and underestimated the overall downward trend in cancer screenings across the country leading up to 2020.