In a recent study published in JAMA Oncology, researchers used data from all 50 states of the United States (US) and the District of Columbia to compare observed and predicted cancer 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) has significantly affected cancer identification in the US, with a lack of nationwide studies based on cancer registries.
Although the discovery of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in 2019 caused enormous disruption, the dangers of cancer persist.
The decrease in cancer incidence in 2020 may not mean a decrease in cancer cases, but rather undiagnosed new tumors.
Although researchers anticipated the negative correlation of responses to the COVID-19 pandemic with cancer detection, the data needed to quantify this extent were unavailable in the United States until recently.
About the research
In the current cross-sectional, population-level study, researchers used data from the United States Cancer Statistics database for the period 2001-2020 to examine delays and discontinuities in cancer diagnosis during the initial wave of COVID-19 .
The team examined trends using data from invasive cancer diagnosis cases documented by United States Cancer Statistics between January 1, 2018, and December 31, 2020, age-adjusted for the standard United States population in 2000. They examined data from July 6 to 28, 2023.
Study exposures included age, sex, race, urbanization, and state response to the pandemic during the period of cancer diagnosis.
The researchers performed time-series forecasting to generate predicted cancer cases between March 1 and December 31, 2020, based on pre-pandemic patterns (between January 2018 and February 2020).
They excluded Nevada and Indiana because of missing data for 2020 and patients with an unclear month of cancer diagnosis. They examined patients diagnosed with invasive cancer from 2018 to 2020 and calculated the monthly cancer incidence across all sites.
The team used the World Health Organization’s 2008 International Classification of Diseases (ICD-O-3) to identify new cancer sites and cluster sites.
They identified screenable malignancies based on the recommendations of the United States Preventive Services Task Force: lung and bronchus, colon and rectum, breast (females only), and cervix.
The researchers estimated incidence rates for the eligible population stratified by age, sex, urbanicity, race, state of residence, and state-level responses to the COVID-19 pandemic and tumor stage at detection.
They categorized participants’ age according to Medicare criteria (under 65 or ≥65 years), race using Race Recode variables, and urban setting using the 2013 rural-urban continuum codes. The team grouped COVID-19 responses by state of residency based on the length of stay-at-home rule in each state in spring 2020.
They converted monthly age-stratified cancer cases observed between January 2018 and December 2020 into time series by cancer group and site by fitting the time series to autoregressive integrated moving average (ARIMA) statistical models for analysis.
Results
The study examined 1,297,874 tumor cases reported in the United States between March 1 and December 31, 2020, giving a cancer incidence rate of 327 cases per individual.
Observed cancer incidence rates across all sites were 29% lower than predicted during the peak of the SARS-CoV-2 pandemic response (between March and May 2020), 6.3% more lows between June and December 2020 and 13% lower overall in the first ten months of the pandemic. The finding showed 134,395 likely undetected malignancies during this period.
Prostate cancer is the type most likely to be missed (22,950 cases), followed by breast cancer (16,870 cases) and lung cancer (16,333 cases). Screenable malignancies had a 14% lower overall rate than predicted.
Breast cancer rates improved from previous patterns after the first three months of COVID-19, while rates of lung cancer, colorectal cancer, and cervical cancer remained low.
Between March and May 2020, states with very robust pandemic responses saw significantly more outages; however, these variations were not significant by December 2020 for all sites except pancreatic, kidney, and lung cancer.
Every cancer site examined showed statistically significant disruptions between March and May 2020, with melanoma diagnoses 43% fewer than predicted.
The incidence of late-stage lung cancer is much higher than that of breast and cervical malignancies, but equal to that of late-stage colorectal cancer.
From March 1 to December 31, 2020, all non-screenable malignancies had statistically significant early- and late-stage disruptions. Between March 1 and May 31, 2020, cancer incidence rates across all sites were significantly higher in states with more limited responses to COVID-19 and among people age 65 and older.
Conclusion
Overall, the study results show that the SARS-CoV-2 pandemic in the United States has significantly affected cancer incidence, with more than 13,000 cases going undetected between March and December 2020.
This knowledge is critical to cancer prevention and control efforts, highlighting the importance of preparing for a future catastrophe in influencing cancer diagnosis.
The study found significant reductions in the incidence of early- and late-stage colorectal cancer, with female breast cancer showing a rebound during the most stringent phase of the pandemic response. Government programs should focus on re-engaging patients and reducing missed appointments.
