Cancer diagnoses in the United States dropped almost 10% below expected rates in 2020 as people missed annual screenings, and medical clinics closed in the early months of the pandemic.
New research from the University of Kansas published late last week in JAMA Network Open suggests the lag of diagnoses carried into 2021. And, in the first 2 years of the pandemic, the country saw almost 150,000 potentially undiagnosed cancer cases.
"Unfortunately, this research shows that rates of cancer incidence in the U.S. have not rebounded as well as we would have hoped after the second year of the pandemic," said first study author Todd Burus, MAS, in a University of Kentucky press release. "While we still don't know what impact this will have on long-term outcomes, prolonged disruptions in diagnoses of certain cancers are certainly concerning and something that needs to be addressed."
Earlier this year, Burus and senior author Krystle Lang Kuhs, PhD, MPH, both from the Markey Cancer Prevention and Control Research Program at the University of Kentucky, published research showing an estimated 134,000 missed cancer diagnoses in the first 10 months of the COVID-19 pandemic.
The new study builds on those findings and uses data from the National Cancer Institute's Surveillance, Epidemiology, and End Results 22 (SEER-22) to track cancer rates of invasive cancer diagnosed from January 1, 2020 through December 31, 2021. The SEER-22 database covers 47.9% of the US population.
Overall, SEER-22 registries noted 1,578,697 cancer cases in 2020 and 2021. Cancer incidence rates were 9.4% lower than expected in 2020 (95% prediction interval [PI], 8.5% to 10.5%), 2.7% lower than expected in 2021 (95% PI, 1.4% to 3.9%), and 6.0% lower than expected across both years combined (95% PI, 5.1% to 7.1%), the authors said.
Five cancers remained underdiagnosed
Eleven types of cancer were included in the database registry, and five of these types showed significant lags in diagnoses through 2021: lung, cervical, kidney, and bladder cancer and lymphoma.
Lung cancer diagnoses were 9.1% lower than expected, and cervical cancer diagnoses 4.5% lower. Early-stage diagnoses especially were lagging for lung and cervical cancers.
Of cancers commonly detected through annual screenings, only female breast cancer showed significant recovery in 2021, exceeding expected rates by 2.5% (95% PI, 0.1% to 4.8%).
By the end of 2021, rates of cancer diagnoses for women, adults ages 65 and older, and non-Hispanic Asian and Pacific Islanders returned to prepandemic levels.
We estimate that overall diagnoses of new cancer cases still fell short of expected levels during the second year of the pandemic.
"Despite experiencing less disruption than in 2020, we estimate that overall diagnoses of new cancer cases still fell short of expected levels during the second year of the pandemic," the authors wrote. "Continued reductions in early-stage lung and cervical cancer rates are particularly concerning, as is the nonsignificant suggestion of increased rates of late-stage diagnoses among 3 of the 4 screening-detected cancers.
"Overall, our findings suggest that pandemic-related disruptions to cancer diagnoses in the US lasted well beyond the first few months of 2020."
