In a recent study published in JAMA Oncology, researchers used data from all 50 United States (US) states and the District of Columbia to compare observed and projected cancer rate patterns from March to December 2020.
Study: Undiagnosed Cancer Cases in the US During the First 10 Months of the COVID-19 Pandemic. Image Credit: Image Point Fr/Shutterstock.com
Background
The coronavirus disease 2019 (COVID-19) significantly influenced cancer identification in the US, with a lack of countrywide studies based on cancer registries.
Although the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) detection in 2019 caused enormous disruptions, cancer dangers persisted.
A drop in cancer incidences during 2020 may not imply a decrease in cancer occurrence but rather undiagnosed new tumors.
Although researchers expected the negative correlation of the COVID-19 pandemic responses with cancer detection, the data required to quantify this extent was inaccessible in the United States until recently.
About the study
In the present population-level cross-sectional study, researchers used the 2001-2020 United States Cancer Statistics database data to examine the delays and interruptions in cancer diagnosis during the initial COVID-19 wave.
The team examined trends utilizing data from invasive cancer diagnostic cases documented by the United States Cancer Statistics between 1 January 2018 and 31 December 2020, age-adjusted for the United States Standard Population in 2000. They studied data from 6 to 28 July 2023.
The study's exposures included age, gender, race, urbanization, and the state's response to the pandemic during the cancer diagnosis period.
The researchers performed time-series forecasting to generate predicted cancer incidences between 1 March and 31 December 2020 based on prepandemic patterns (between January 2018 and February 2020).
They excluded Nevada and Indiana due to 2020 data unavailability and patients with an unclear month of cancer diagnosis. They investigated patients with invasive cancer diagnoses from 2018 to 2020 and calculated monthly all-site cancer incidence.
The team used the World Health Organization's 2008 International Classification of Diseases for Oncology, Third Revision (ICD-O-3) to identify new cancer sites and site groupings.
They identified screenable malignancies based on the United States Preventive Services Task Force recommendations: lung and bronchus, colon and rectum, breast (only in women), and cervix uteri.
The researchers assessed incidence rates for the eligible population stratified by age, gender, urbanicity, race, state of residency, and state-level responses to the COVID-19 pandemic and the tumor stage at detection.
They categorized participant age by Medicare criteria (below 65 or ≥65 years), race using Race Recode variables, and urbanicity using the Rural-Urban Continuum Codes of 2013. The team grouped COVID-19 responses by state of residency based on the duration of stay-at-home rule enforcement in each state in spring 2020.
They converted the monthly age-stratified cancer incidences observed between January 2018 and December 2020 into time series by cancer group and site, fitting the time series to autoregressive integrated moving average (ARIMA) statistical models for analysis.
Results
The study examined 1,297,874 tumor cases recorded in the United States between 1 March and 31 December 2020, yielding a cancer incidence rate of 327 cases per individual.
The observed all-site cancer incidence rates were 29% lower than projected during the peak of the SARS-CoV-2 pandemic response (between March and May 2020), 6.3% lower between June and December 2020, and 13% lower overall over the pandemic's initial ten months. The finding indicates 134,395 probably undetected malignancies throughout that period.
Prostate cancers were the most possibly missed type (22,950 cases), followed by breast cancers (16,870 cases) and lung cancers (16,333 cases). Screenable malignancies had a 14% lower overall rate than predicted.
Breast cancer rates improved from prior patterns after the initial three months of COVID-19, while levels of lung, colorectal, and cervical cancers remained low.
Between March and May 2020, states with highly stringent pandemic responses saw considerably more disruptions; however, these variations were non-significant by December 2020 for all locations except pancreatic, renal, and lung cancers.
Every cancer location studied exhibited statistically significant disturbances between March and May 2020, with melanoma diagnoses being 43% fewer than predicted.
Disruptions in late-stage lung cancer diagnoses were much higher than in breast and cervical malignancies but equal to those in late-stage colorectal cancer incidence.
From March 1 to December 31, 2020, all non-screenable malignancies had statistically significant disturbances in the early and late stages. Between March 1 and May 31, 2020, all-site cancer incidence rates were considerably higher in states with more restricted COVID-19 responses, as well as among those aged 65 and over.
Conclusion
Overall, the study findings showed that the SARS-CoV-2 pandemic in the United States considerably influenced cancer incidence rates, with over 13,000 cases going undiscovered between March and December 2020.
This knowledge is critical for cancer prevention and control efforts, underscoring the importance of future catastrophe preparation in influencing cancer diagnosis.
The study discovered significant decreases in early- and late-stage colorectal cancer incidence, with female breast cancer demonstrating rate recovery during the most stringent pandemic response phase. Government programs should focus on reengaging patients and reducing missed appointments.
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