Cancer Diagnoses Significantly Decreased in First Few Months of COVID-19 Pandemic

In the first few months of the COVID-19 pandemic, there was a significant decrease in cancer diagnosis among breast, colon, and rectal cancers, according to the results of a study published in JAMA Network Open. However, investigators said that the drop was followed by a recovery at most cancer sites included in the study.¹

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According to the results of a separate study published in the European Journal of Epidemiology, there was an overall decrease of approximately 37.3% for diagnostic tests during the pandemic and a 27% decrease for cancer diagnosis.² The investigators of this study stated that the delay in cancer diagnoses could increase the number of avoidable deaths related to the disease and emphasized the need to assess the impact of the pandemic on cancer treatment and mortality.²

In the current study, the authors noted that the missed or delayed diagnoses have the potential for more advanced disease and inferior outcomes, including lower survival rates. Previously, the same authors found a 23% decrease in new cancer diagnoses, an 83% decrease in Papanicolaou tests, an 81% decrease in fecal occult blood tests, and a 54% decrease in mammograms at the beginning of the pandemic in Manitoba, Canada.¹

The study authors sought to examine the association between the COVID-19 pandemic and incidence of cancers. In the study, investigators used a population-based cross-sectional design, including data from the Manitoba Cancer Registry for individuals in Canada. All individuals included were diagnosed with cancer from January 1, 2015, until December 31, 2021.¹

Individuals in the study had breast, colon, rectal, or lung cancers and were grouped by age: younger than 50 years, 50 to 74 years, and 75 years and older. There were a total of 48,378 individuals included in the study.¹

Investigators found an approximately 23% decrease in overall cancer incidence in April 2020, with a 46% decline for breast cancer, 35% for colon cancer, 47% for rectal cancer, 50% for head and neck cancer, 65% for melanoma, and 33% for endocrine cancer diagnoses. However, there was a 12% increase for hematological cancer and 8% for diagnoses of cancers with unknown primary sites, according to the study results.¹

In June 2020, investigators did not observe any significant differences between the fitted and counterfactual cancer incidence.¹

For breast cancer, there was no association of incidence for those aged younger than 50 years, a decrease of 46% in April 2020 and 73% in May 2020 for those aged 50 to 74 years, and a 20% sustained decrease for women aged 75 years and older.¹

Furthermore, lung cancer incidence remained stable until December 2020, but decreased by 11% after. There was only an association for the 75 years of age and older group, decreasing by 46% in April 2020.¹

The brain and central nervous system and urinary cancer diagnoses decreased consistently from April 2020 to December 2021, by 26% and 12%, respectively. Investigators noted that there were no associations for gynecologic, other digestive, or pancreatic cancer incidences.¹

Approximately 5.3% of cancers had an estimated deficit as of December 2021, with the largest estimates being for breast at 14.1%, colon at 12.2%, and lung at 7.6% cancers.¹

Investigators said that the deficits for high-fatality cancers need attention from health care organizations. They also called for additional observational studies in other regions to determine the effects of the COVID-19 pandemic on cancer incidence.¹

References

1. Decker KM, Feely A, Bucher O, Czaykowski P, et al. New cancer diagnoses before and during the COVID-19 pandemic. JAMA Netw Open. 2023;6(9):e2332363. doi:10.1001/jamanetworkopen.2023.32363
2. Angelini M, Teglia F, Astolfi L, Casolari G, Boffetta P. Decrease of cancer diagnosis during COVID-19 pandemic: a systematic review and meta-analysis. Eur J Epidemiol. 2023;38(1):31-38. doi:10.1007/s10654-022-00946-6