COVID-19 and Rates of Cancer Diagnosis in the US.

IMPORTANCE: US cancer diagnoses were substantially lower than expected during the COVID-19 pandemic in 2020. A national study on the extent to which rates recovered in 2021 has not yet been conducted.

OBJECTIVE: To examine observed vs expected cancer rate trends for January 2020 to December 2021.

DESIGN, SETTING, AND PARTICIPANTS: This cross-sectional, population-based study of cancer incidence trends used the Surveillance, Epidemiology, and End Results 22 (SEER-22) Registries Database, which covers 47.9% of the US population. Included individuals were those with an invasive cancer diagnosis reported to registries included in SEER-22 between January 1, 2000, and December 31, 2021.

EXPOSURES: Age, sex, race and ethnicity, urbanicity, and stage at diagnosis.

MAIN OUTCOMES AND MEASURES: Expected cancer incidence rates were measured for the COVID-19 pandemic years of 2020 and 2021 from prepandemic trends using ensemble forecasting methods. Relative difference between observed and expected cancer incidence rates and numbers of potentially missed cases were measured.

RESULTS: The SEER-22 registries reported 1 578 697 cancer cases in 2020 and 2021, including 798 765 among male individuals (50.6%) and 909 654 among persons aged 65 years or older (57.6%). Observed all-sites cancer incidence rates were lower than expected by 9.4% in 2020 (95% prediction interval [PI], 8.5%-10.5%), lower than expected by 2.7% in 2021 (95% PI, 1.4%-3.9%), and lower than expected by 6.0% across both years combined (95% PI, 5.1%-7.1%), resulting in 149 577 potentially undiagnosed cancer cases (95% PI, 126 059-176 970). Of the 4 screening-detected cancers, only female breast cancer showed significant recovery in 2021, exceeding expected rates by 2.5% (95% PI, 0.1%-4.8%), while significant reductions remained for lung cancer (9.1% lower than expected; 95% PI, 6.4%-13.2%) and cervical cancer (4.5% lower than expected; 95% PI, 0.4%-8.0%), particularly for early stage at diagnosis. Rates of all-sites cancer incidence returned to prepandemic trends in 2021 among female individuals, persons aged younger than 65 years, and persons of non-Hispanic Asian and Pacific Islander race and ethnicity.

CONCLUSIONS AND RELEVANCE: This population-based cross-sectional study of US cancer incidence trends found that rates of diagnosis improved in 2021 but continued to be lower than expected, adding to the existing deficit of diagnosed cases from 2020. Particular attention should be directed at strategies to immediately increase cancer screenings to make up lost ground.