Screening declines after pandemic onset may result in ‘increased avoidable cancer deaths’

Widespread reductions in cancer screenings during the COVID-19 pandemic may be associated with delayed cancer diagnoses and increased mortality for breast, cervical and colon cancers, according to study results published in JAMA Oncology.

Rationale and methods

Federica Teglia, MD, physician in the department of medical and surgical sciences at University of Bologna in Italy, and colleagues sought to examine the effect of the COVID-19 pandemic on worldwide cancer screening.

The systemic review and meta-analysis included 39 observational studies and articles published between 2020 and 2021 with data from cancer registries that compared the number of screening tests for breast, cervical and colorectal cancer performed before and during the pandemic.

Researchers calculated the weighted average of the percentage variation in screening tests over five periods between January and October of 2020 compared with the prepandemic period. They also performed a stratified analysis according to geographic area, time period and type of setting.

Key findings

Results showed an overall decrease in breast cancer screening (46.7%; 95% CI, 55.5 to 37.8), colorectal cancer screening (44.9%; 95% CI, 53.8 to 36.1) and cervical cancer screening (51.8%; 95% CI, 64.7 to 38.9) during the pandemic period.

Moreover, researchers identified a U-shaped temporal trend in the decreases for all three cancer types, with a negative peak in April 2020 for mammography (74.3%), as well as for colonoscopy and fecal occult blood test or fecal immunochemical test (69.3%). They also noted a negative peak in March 2020 for Pap test or HPV test (78.8%).

A significant decrease in colorectal cancer screening persisted after May 2020, with a decline of 23.4% (95% CI, 44.4 to 2.4) from June to October 2020.

Differences varied according to geographic area, with greater percentage variation in South America compared with North America for cervical cancer screening (62.4% vs. 44.7%) and breast cancer screening (51.1% vs. 44.6%). In addition, researchers noted greater association between the pandemic and cancer screening in studies conducted in hospitals or other clinic settings compared with population-based studies, particularly for breast cancer screening (62% vs. 41.6%; P = .03).

Limitations of the study included the considerable heterogeneity between countries in terms of screening protocols, accessibility to services and participation of the target population, lockdown measures and incidence of COVID-19 and its temporal trend.

Potential implications

Researchers acknowledged the need for additional research to clarify long-term implications of variations in cancer screenings and adopt adequate public health strategies.

“The most concerning potential effect of a decrease in cancer screening is an increase in cancer mortality, as estimated in the United States,” researchers wrote. “The interruption of cancer screening could delay diagnosis of tumors, causing a shift to more advanced stages at diagnosis. Furthermore, this could be associated with increased avoidable cancer deaths, aggravate the patients’ discomfort and disease burden, and be associated with increased workload for medical personnel and increased costs for the health care system.”