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Cancer Diagnosis Rates Remain Lower Than Expected Due to COVID-19 Pandemic
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In 2021, cancer diagnosis rates remained low after major disruptions during the first year of the COVID-19 pandemic.
A population-based cross-sectional study of cancer incidence trends in the United States found that the rates of cancer diagnosis improved in 2021 after major disruptions due to the COVID-19 pandemic but have continued to be lower than expected and increased the existing deficit of diagnosed cases, according to results published in the Journal of the American Medical Association.1
Cancer diagnoses declined due to the COVID-19 pandemic. | Image credit: © Halfpoint | stock.adobe.com
The disruptions in cancer cases since the coronavirus pandemic have been well-documented in previously published literature. In a previous study by the same research team, they found that all-sites cancer incidence in the US was significantly lower than expected in March through December 2020.2
The investigators identified 134,395 potentially undiagnosed cancer cases, a large number representing a major unmet need. Differences in cancer diagnosis rates were even greater among certain cancer stages, specific cancer sites, and population subgroups. It is unknown whether cancer rates had recovered since the COVID-19 pandemic.1,2
In the study, the investigators sought to gain a better understanding of the lasting association of COVID-19 with cancer burden in the US by analyzing observed cancer incidence rates from a list of US cancer registries. They also aimed to better assess the state of cancer diagnoses during the second year of the pandemic.1
A total of 1,678,697 cancer cases reported by the National Cancer Institute’s Surveillance, Epidemiology, and End Results 22 (SEER-22) Registries Database were included in the study. Using their final model, they estimated that all-sites cancer incidence was 9.4% lower than expected in 2020 (95% PI, 9.5%-10.5%) and 2.7% lower in 2021 (95% PI, 1.4%-3.9%), resulting in a significant reduction of 6.0% across both years (95% PI, 5.1%-7.1%).1
In terms of cases missed, the investigators determined that this reduction in diagnoses equated to 149,577 potentially undiagnosed cases during the first 2 years of the coronavirus pandemic (95% PI, 126,059-176,970), with 33,226 undiagnosed cases occurring in 2021 alone (95% PI, 17,513-49,463).1
Diagnosis rates by stage were estimated to be significantly lower than expected for both early- and late-stage disease in 2020. However, there were significantly lower rates among early-stage diagnoses than among late-stage diagnoses, and in 2021 there was no significant disruption to either early- or late-stage cancer diagnoses.1
Furthermore, cancer diagnosis disruptions were observed across every subgroup that was categorized, including by age, race and ethnicity, sex, and urbanity. By 2021, all-sites cancer incidence returned to pre-pandemic levels in females, people younger than 65 years, and non-Hispanic Asian and Pacific Islanders, but remained significantly lower among males, people 65 years and older, Hispanic individuals, and non-Hispanic Black and White individuals.1
To the knowledge of the investigators, this is the first analysis from high-quality US cancer registry data on whether cancer incidence rates recovered to pre-COVID-19 pandemic trends following 2020. “Overall, our findings suggest that pandemic-related disruptions to cancer diagnoses in the US lasted well beyond the first few months of 2020,” the investigators wrote.1
One major factor leading to a drop in cancer diagnosis rates was fears associated with COVID-19 infections, according to several studies of delayed medical care during 2020. This fear resonated particularly in female and younger individuals. Correspondingly, as COVID-19 vaccines became widely available in the US in March and April 2021, young females had some of the highest increases in rates of diagnosis.3
Though the wide proliferation of COVID-19 vaccines and transition of the pandemic to an endemic phase has likely contributed to an uptick in cancer diagnosis rates, the investigators cautioned that, as these results are coming to light 2 years after they have occurred, there needs to be more investments made in nationwide cancer surveillance. These would help “increase the speed, quality, and consistency” or cancer data.1
In the meantime, work must be done to make up for the deficit in cancer diagnoses across the country due to the pandemic. “Particular attention should be directed at strategies to immediately increase cancer screenings to make up lost ground and prevent a future surplus of late-stage diagnoses,” the investigators concluded.1
