SEER 22 Registries Database analysis of impact of COVID-19 pandemic on rates of cancer diagnosis

US cancer diagnoses were substantially lower than expected during the COVID-19 pandemic in 2020. Analysis of the SEER 22 Registries Database examined the observed versus expected cancer rate trends for January 2020 to December 2021. The analysis found that rates of observed cancer diagnoses improved in 2021 but still remained a significant 2.7% lower than expected. Among screening-detected cancers, female breast cancer showed significant rate recovery in 2021, colorectal cancer returned to prepandemic trends, and significant reductions in diagnoses remained for lung and cervical cancers. The authors conclude that cancer cases in the US continued to be underdiagnosed during the second year of the COVID-19 pandemic, adding to the existing deficit of diagnosed cases from 2020.