Markey study reveals extent of undiagnosed cancer cases due to COVID-19 pandemic

Over 134,000 cancer cases went undiagnosed in the U.S. during the first 10 months of the COVID-19 pandemic, according to a new University of Kentucky Markey Cancer Center study. 

The report published in JAMA Oncology Feb. 22 provides the first estimates of missed cancer diagnoses in 2020 using nationwide surveillance data.

Researchers have expected impacts to cancer detection as a result of delayed screenings and missed health care appointments due to the COVID-19 pandemic, but the extent of this impact had not been quantified until recently. The study’s findings foreshadow even greater consequences.

“The longer cancer exists undetected, the lower the chances of positive patient outcomes. Every missed detection is a lost opportunity to beat cancer at its most treatable stage,” said the paper’s senior author Krystle Lang Kuhs, Ph.D., co-leader of the UK Markey Cancer Center’s Cancer Prevention and Control Research Program and associate professor in the UK College of Public Health. “This research reminds us to prioritize our health and get back on track with recommended cancer screenings and routine office visits so we can live longer, healthier lives.”

Findings from this report will help to inform where the U.S. health care system can make up ground in cancer screening and detection and give insight on how similar disruptions could impact cancer diagnoses in the future.

The research underscores the importance of timely dissemination of data, says Todd Burus, the study’s lead author and part of Markey Cancer Center’s Community Impact Office.

"It is unfortunate that we are only able to perform this assessment over two years after the fact,” said Burus. “We must invest the resources necessary to have more timely tracking of trends in cancer incidence so that we can target responses to the places they're needed sooner."

The study relied on data from the U.S. Cancer Statistics Public Use Database June 2023 release—the first release available with 2020 cancer incidence data for all 50 states. Using trends from previous years, the team calculated the expected cancer rates for March through December 2020 and compared this with what was actually reported.

Results showed that overall cancer diagnoses were 13% lower than expected during those 10 months, including a 28.6% reduction from expected during the period of widespread stay-at-home orders in March to May 2020.

Researchers also examined incidence rates by cancer type and stage of diagnosis, and among different populations. Key findings include:

• Prostate, female breast, and lung cancers had the largest numbers of potentially missed cases during the 10-month period at 22,950 cases, 16,870 cases and 16,333 cases, respectively.
• Cancers with recommended, high-evidence screenings (female breast, cervical, colorectal and lung) saw a total rate reduction of 13.9% versus expected. Rates of female breast cancer showed signs of recovery to previous trends following the first three months of the pandemic, but levels remained suppressed for cervical, colorectal and lung cancers throughout the 10 month period.
• Significant reductions occurred among both early and late-stage diagnoses of most cancer sites examined.
• States that implemented stay-at-home orders in excess of six weeks saw a greater disruption to cancer diagnoses than those that undertook less restrictive measures, particularly among lung, kidney and pancreatic cancers.

The paper’s authors also stress the need to continue following this data in the coming years to understand how undetected cases from 2020 impact future trends in cancer mortality and survival.

“There will undoubtedly—and unfortunately—be a subsequent bump in cancer mortality,” the authors note. “How much, and for how long, will provide a more complete picture of the consequences of COVID disruptions on the burden of cancer in the U.S.”