There are now several pieces of evidence that the harm caused by coronavirus disease 2019 (COVID-19) goes beyond an immediate organic damage, but may generate a variety of additional “collateral” damages. This last category of health problems includes delays in diagnosis due to social isolation measures (e.g. home segregation, lockdowns and curfews), as well as to the fear of going to crowded places such as hospitals and the resulting backlog of patients, which have caused a significant impact on population screening, including colorectal cancer screening during the early period of the pandemic (1). In particular, a recently published article by Brenner et al. showed a remarkable decrease in colorectal cancer diagnoses in Saarland/Germany during the COVID-19 pandemic until the second quarter of 2021 (2). These results overlap with those published in the US, where, it was estimated that colorectal cancer screenings decreased by around 85% in the early phase of the COVID-19 pandemic (3). Therefore, it would be expected that such a reduction in patient access to colorectal cancer screening could have generated a negative impact on subsequent diagnoses and survival probabilities. To this end, we report here the recent statistics on colorectal cancer-related deaths in the US.
We electronically searched the latest updated version of the US Centers for Disease Control and Prevention (CDC) online database WONDER (Provisional Multiple Cause of Death Data; years 2018-2023), which reports mortality data for the entire country. Data originate from death certificates for US residents (with a single underlying cause of death and demographic data). Our search was performed with “year” as the first variable (from 2018 to 2023) and specific ICD-10 codes for colorectal cancer as the second variable (from C18 to C20). Mortality data were expressed as age-adjusted death rates (×100,000) and their relative 95% confidence interval (95%CI). Values were analyzed with one-way analysis of variance (ANOVA) and Tukey post-hoc test. The study was conducted in accordance with the Declaration of Helsinki and in accordance with the terms of the relevant local legislation.
The results of our search in the CDC WONDER online database (years 2018-2021) are summarized in Figure 1. The age-adjusted death rate for colorectal cancer displayed a gradual decrease from 2018 (13.06×100,000; 95%CI, 12.95-13.18×100,000) to 2019 (12.76×100,000; 95%CI, 12.64-12.87×100,000) and 2020 (12.55×100,000; 95%CI, 12.44-12.66×100,000). This favorable trend was then reversed in 2021, when the age-adjusted death rate for colorectal cancer increased to 12.94×100,000 (95%CI, 12.83-13.06×100,000), decreasing to 12.58×100,000 (95%CI, 12.47-12.68) in 2022 and increasing again to 12.75×100,000 (95%CI, 12.64-12.86×100,000) in 2023. The variation throughout the observation period was statistically significant (f=12.20; p<0.001). In Tukey Post-hoc Test, the reduction observed in 2019 (p=0.003) and 2020 (p<0.001) was statistically significant compared to the year 2018, while the increase observed in 2021 was statistically significant compared to the year 2020 (p<0.001). The further reduction observed in 2022 was then statistically significant compared to the year 2021 (p<0.001). A statistically significant reduction was also observed in 2022 (p<0.001) and 2023 (p=0.001) compared to the year 2018. No other statistically significant differences could be seen across other years comparisons.
The results of our analysis of the CDC-WONDER online database show that the COVID-19 pandemic has likely had a negative impact on early mortality from colorectal cancer, as shown by the significant increase in the age-adjusted death rate recorded in 2021, reversing the otherwise favorable downward trend of the previous three years. A further, although not yet statistically significant (p=0.272), increase was recorded between the years 2022 and 2023, which needs to be monitored closely as it may reflect a second peak of late colorectal cancer mortality due to delayed diagnosis of a number of patients with curable disease.