Cancer incidence trends for 2021 have mostly reverted to pre-pandemic levels, according to a study conducted by the National Institutes of Health (NIH). However, the research found little evidence of a resurgence in diagnoses that would explain the drop in 2020, a year in which screening and other medical services faced interruptions. An exception to this trend was noted in breast cancer, where an increase in advanced-stage diagnoses was observed in 2021. This study was published on September 24, 2024, in the Journal of the National Cancer Institute.
A prior study indicated a sharp decline in new cancer diagnoses in early 2020, along with a decrease in pathology reports. This suggested that many cancers were not being diagnosed in a timely manner. To assess whether these missed diagnoses were addressed in 2021—potentially as more advanced cases—researchers from NIH’s National Cancer Institute (NCI) compared the actual cancer incidence rates for 2021 with the expected rates based on pre-pandemic trends, using data from NCI’s Surveillance, Epidemiology, and End Results Program.
A complete recovery in cancer incidence would be indicated by an increase that surpasses pre-pandemic levels (often referred to as a rebound) to compensate for the missed diagnoses. The researchers analyzed cancer overall, as well as five major types that differ in their detection methods: through screening (female breast and prostate cancer), via symptoms (lung and bronchial, and pancreatic cancer), or incidentally during other medical treatments (thyroid cancer).
The findings showed that overall cancer incidence rates and those for most specific cancers nearly reached pre-pandemic figures, but there was no significant rebound to account for the declines seen in 2020. Notably, while there was an increase in new diagnoses of advanced breast cancer in 2021, there was also some indication of a rise in advanced pancreatic cancer diagnoses. In contrast, new thyroid cancer diagnoses in 2021 continued to remain below pre-pandemic levels.
The researchers concluded that 2021 was a transitional year still influenced by new COVID-19 variants and waves of infections, which continued to affect healthcare services. They emphasized the importance of ongoing monitoring to understand the long-term effects of the pandemic on cancer diagnoses and outcomes.
