New diagnoses of six major cancer types in the United States fell abruptly in early 2020, coinciding with the start of the COVID-19 pandemic, according to findings from part 2 of the latest Annual Report to the Nation on the Status of Cancer. The volume of pathology reports also declined sharply in early 2020, suggesting that fewer cancer screenings and other cancer-related procedures were performed during that time. Taken together, the findings suggest that many cancers were not being diagnosed in a timely manner during the early part of the COVID-19 pandemic, likely due to interruptions in medical care.
This study is one of the largest to date using population-based data from central cancer registries to assess the impact of the COVID-19 pandemic on cancer incidence (new diagnoses of cancer) in the United States. The report appeared September 27, 2023, in Cancer.
Part 1 of the latest report, which focused on national cancer statistics, was released in October 2022.
Part 2 of the latest report focuses on changes in cancer diagnoses in the United States during the first year of the COVID-19 pandemic. The authors suggest that these changes were due in part to interruptions in medical care. In particular, early 2020 saw a decline in cancer screenings. In addition, diagnoses made as a result of early symptoms or in the course of routine medical visits may have been delayed when people held off on seeing their doctors.
The authors analyzed cancer incidence data for 2015 to 2020 using data from select population-based cancer registries that participate in CDC’s National Program of Cancer Registries or NCI's Surveillance, Epidemiology, and End Results (SEER) Program.
The authors compared the number of newly diagnosed cases of cancer in 2020 with what was expected based on previous years. They looked at female breast, lung, and colorectal cancers, which are often diagnosed through screening tests or other forms of early detection that may have been disrupted by the pandemic; thyroid and prostate cancers, which are often diagnosed incidentally; and pancreatic cancer, which is usually diagnosed when the patient presents with symptoms. The authors also compared the volume of electronic pathology reports sent to central cancer registries in 2020 with the volume sent in 2019.
From March to May 2020, new cases of all six cancer types fell sharply. By July 2020, however, diagnoses of all cancer types except prostate cancer had returned to pre-pandemic levels, with little difference between observed and expected numbers during the second half of the year.
Over the same period in early 2020, the volume of electronic pathology reports also declined steeply before returning to pre-pandemic levels. Because these reports are transmitted automatically to cancer registries, the findings suggest that the decline in new cancer diagnoses was not due to delays in reporting caused by pandemic disruptions but rather to missed screenings and delays in other cancer-related procedures.
The authors also looked at declines in new cancer cases by cancer stage at diagnosis, sex, age, and population group. For each cancer type in the study, new cases of early-stage cancers fell more sharply than new cases of advanced cancers. The declines were greatest for the cancers typically diagnosed through screening (female breast, lung, and colorectal cancer). For example, 7,147 cases of early-stage colorectal cancer were expected to be diagnosed in 2020, but only 5,983 cases were diagnosed—meaning that potentially more than 16% of early-stage colorectal cancer cases weren’t caught.
However, missed screenings only partly explain the observed declines in new cancer cases. Fewer in-person medical visits likely also contributed to the underdiagnoses, particularly for diseases such as thyroid cancer, which is often caught incidentally during other medical procedures.
Asian or Pacific Islander populations had greater declines in new cases of all cancer types, except for pancreatic cancer, compared with White, Black, and American Indian or Alaska Native populations. Another notable population group difference was a greater decline in prostate cancer diagnoses among White people than Black people.
