COVID-19 pandemic caused significant variations in cancer reporting

Reviewed by Emily Henderson, B.Sc.Apr 12 2023

New research from the American College of Surgeons (ACS) outlines significant ways that the COVID-19 pandemic destabilized usual patterns of cancer care as reported in the National Cancer Database (NCDB), one of the largest cancer registries in the world used by thousands of hospitals and centers around the country to inform and improve the quality of cancer care.

The research, published today in JAMA Surgery as a Special Communication article, describes specific ways that NCDB data models were impacted by the pandemic, offering guidance to centers across the country on how to interpret data from 2020 and onwards. The research also paints a much larger picture of the many disruptions caused by the pandemic outside of the immediate emergency of treating COVID-19 patients.

More than 1.1 million Americans have died from COVID-19, and though pandemic-related restrictions are easing throughout the country, the effects of the pandemic on chronic diseases such as cancer remain largely unknown.

While monitoring real-time data submissions, the ACS Cancer Programs, which manages the NCDB with the American Cancer Society, noted variances in new cancer diagnoses in the first several months of 2020. These variances marked a significant change from the historically stable dataset, which collects more than 1.5 million new cancer cases each year, representing more than 70% of all cancer cases in the United States.

"The pandemic really changed our approach to healthcare in general, but this was especially true for cancer patients who found their care disrupted and for undiagnosed patients who had to delay screening visits," said first author Sharon Lum, MD, MBA, FACS, former Vice Chair of the Quality Integration Committee of the ACS Commission on Cancer (CoC) and Chair of the Department of Surgery at Loma Linda University School of Medicine. "Many clinicians in the cancer world knew that care for cancer patients was disrupted in many significant ways. But we didn't really have any solid reporting of that. This research was an attempt to validate and report changes in the trajectory of cancer cases captured by the NCDB in the first year of the pandemic."

For the study, researchers reviewed 4,045,097 cancer cases from adults 18 years or older who were diagnosed with cancer and/or received their first-course treatment at a reporting facility from January 1, 2018, through December 31, 2020. Reporting facilities included CoC-accredited programs, excluding Veterans Affairs-affiliated programs.

Our goal was to inform people about what was happening at large in the world of cancer -; to provide a global look similar to how a GPS system tells you where you are across the globe -; so that centers could create context around their specific datasets. Rather than dive into specific hypotheses about what may have occurred for each type of cancer, we wanted this research to serve as a point of reference and context because each hypothesis for cancer is different. Each disease is going to have its own series of hypotheses."

Heidi Nelson, MD, FACS, Medical Director of the ACS Cancer Programs and study co-author

Key findings

The study offers a detailed look into the complexities and variations that occurred in cancer reporting as a result of the pandemic. Among the key findings:

• The COVID-19 pandemic was associated with significant changes in diagnoses of all cancer types in 2020, with a 14.4% overall decline in the number of reported cancer cases in the NCDB compared with the prior year. This decline represents more than 200,000 cancer cases that were not diagnosed and/or treated at CoC facilities.
• These missing cancer cases are expected to appear in 2021 data and beyond, potentially at more advanced stages.
• Overall, the proportion of patients diagnosed with early-stage disease decreased from March to June 2020, followed by a corresponding increase in the proportion of those diagnosed with late-stage disease, peaking in April 2020 and correcting to prior years' percentages by July 2020. However, the 2020 stage distributions for specific types of cancer varied.
• The study identified differences across sociodemographic data. Overall, the proportion of White patients with cancer significantly increased, while the proportion of Asian or Pacific Islander, Hispanic, Black, and other/unknown patients with cancer significantly decreased. This finding suggests that certain racial and ethnic groups were less likely to be diagnosed with cancer and/or receive cancer care, potentially exacerbating existing health disparities in cancer treatment.
• Significant disparities were noted between age groups, with increases in cancer rates in people 60 to 69 years old and 70 to 79 years old, and decreases in age of diagnosis in younger and older age categories throughout 2020. This finding suggests that patients younger than 60 and those older than 80 were less likely to be diagnosed or treated for cancer compared with past years.

Understanding the pandemic's lasting effects

Dr. Lum and Dr. Nelson noted that future research needs to be done to better understand the lasting effects of the pandemic, including how COVID-19 infection impacted or exacerbated chronic diseases, treatment adherence and outcomes, and long-term follow-up of the 14.4% of cancer diagnoses that were not treated as expected in CoC-accredited cancer programs.

Because significant variance was identified in 2020 NCDB data compared with prior years, the authors recommend that centers publishing information with NCDB data include the following disclaimer language in publications using 2020 NCDB data: "This study includes data from the year 2020, the first year of the COVID-19 pandemic. Variability in reporting 2020 cases in the NCDB must be considered when interpreting results."

"My main takeaway is to really look under the hood when using and analyzing NCDB data that from here on out will include data from 2020," Dr. Lum said. "Because what you assume is happening may not actually be happening, and you have to really take a deep dive into the treatment variables and particular disease process to understand how the pandemic affected cancer care in your program."

Future analysis of NCDB data may also reveal more details about the pandemic and provide valuable information to healthcare organizations about how to be better prepared for emergencies.

"Particularly in the first three months of the pandemic, healthcare resources were significantly diverted and hospitals were overwhelmed. There were so many things we didn't know that we weren't prepared for. How could we be?" Dr. Nelson said. "But I don't think we should bury our heads in the sand to what happened, and not be aware of the negative things that happened to patients besides COVID-19 infection. If anything, this data shows us that you didn't have to be a COVID-19 patient to suffer during the pandemic."

This project received no external funding. The NCDB, which is the data source used in the paper, is a joint project of the Commission on Cancer of the American College of Surgeons and the American Cancer Society.