Nationwide participation in FIT-based colorectal cancer screening in Denmark during the COVID-19 pandemic: An observational study
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Curated by eLife
eLife assessment
The authors convincingly demonstrate that, in the absence of any shutdowns, the Danish colorectal cancer screening program experienced only minor decreases in program participation during the COVID-19 pandemic period. This likely ensured ongoing program effectiveness in detecting early colorectal cancers and precancerous polyps. The evidence is solid, as the national screening database was used and only a small proportion of participants were excluded.
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Abstract
Worldwide, most colorectal cancer screening programmes were paused at the start of the COVID-19 pandemic, while the Danish faecal immunochemical test (FIT)-based programme continued without pausing. We examined colorectal cancer screening participation and compliance with subsequent colonoscopy in Denmark throughout the pandemic.
Methods:
We used data from the Danish Colorectal Cancer Screening Database among individuals aged 50–74 years old invited to participate in colorectal cancer screening from 2018 to 2021 combined with population-wide registries. Using a generalised linear model, we estimated prevalence ratios (PRs) and 95% confidence intervals (CIs) of colorectal cancer screening participation within 90 days since invitation and compliance with colonoscopy within 60 days since a positive FIT test during the pandemic in comparison with the previous years adjusting for age, month and year of invitation.
Results:
Altogether, 3,133,947 invitations were sent out to 1,928,725 individuals and there were 94,373 positive FIT tests (in 92,848 individuals) during the study period. Before the pandemic, 60.7% participated in screening within 90 days. A minor reduction in participation was observed at the start of the pandemic (PR = 0.95; 95% CI: 0.94–0.96 in pre-lockdown and PR = 0.85; 95% CI: 0.85–0.86 in first lockdown) corresponding to a participation rate of 54.9% during pre-lockdown and 53.0% during first lockdown. This was followed by a 5–10% increased participation in screening corresponding to a participation rate of up to 64.9%. The largest increase in participation was observed among 55–59 years old and among immigrants. The compliance with colonoscopy within 60 days was 89.9% before the pandemic. A slight reduction was observed during first lockdown (PR = 0.96; 95% CI: 0.93–0.98), where after it resumed to normal levels.
Conclusions:
Participation in the Danish FIT-based colorectal cancer screening programme and subsequent compliance to colonoscopy after a positive FIT result was only slightly affected by the COVID-19 pandemic.
Funding:
The study was funded by the Danish Cancer Society Scientific Committee (Grant number R321-A17417) and the Danish regions.
Article activity feed
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eLife assessment
The authors convincingly demonstrate that, in the absence of any shutdowns, the Danish colorectal cancer screening program experienced only minor decreases in program participation during the COVID-19 pandemic period. This likely ensured ongoing program effectiveness in detecting early colorectal cancers and precancerous polyps. The evidence is solid, as the national screening database was used and only a small proportion of participants were excluded.
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Reviewer #1 (Public Review):
This work by Olesen et al provides a clear and thorough examination of participation in organised colorectal cancer screening in Denmark over 2018-2021, with a particular focus on potential impacts of the COVID-19 pandemic. There is also an analysis by population subgroups that offers additional insight into how the pandemic may have affected participation.
The key strength of this manuscript is access to the presumably complete data from Danish Colorectal Cancer Screening Database, with only a small proportion of individuals being excluded for sensible reasons. Combined with a standard statistical analysis, the results are clear and inarguable.
A weakness is that the manuscript is wholly quantitative. Therefore some of the observations made, particularly for population subgroups, cannot be explained within …
Reviewer #1 (Public Review):
This work by Olesen et al provides a clear and thorough examination of participation in organised colorectal cancer screening in Denmark over 2018-2021, with a particular focus on potential impacts of the COVID-19 pandemic. There is also an analysis by population subgroups that offers additional insight into how the pandemic may have affected participation.
The key strength of this manuscript is access to the presumably complete data from Danish Colorectal Cancer Screening Database, with only a small proportion of individuals being excluded for sensible reasons. Combined with a standard statistical analysis, the results are clear and inarguable.
A weakness is that the manuscript is wholly quantitative. Therefore some of the observations made, particularly for population subgroups, cannot be explained within the scope of this manuscript. The authors have provided hypotheses to explain these, but without further research no firm conclusion can be made.
Another weakness is that, due to the nature of screening, no conclusions can be made on the health impact of COVID-related changes to screening. It is unclear whether small reductions in screening and colonoscopy follow-ups is likely to lead to additional cancers, or later-stage diagnoses.
This manuscript, together with similar analyses in other settings worldwide, provides both an overview of how the COVID-19 pandemic has affected screening, but also potentially guidance for how future potential disruptions should be managed in the cancer screening space. By considering the potential downstream impact of changes to screening, and balancing these against potential harms and resource restrictions associated with (eg) attending health services during a pandemic, policymakers can make informed decisions to manage future shutdowns.
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Reviewer #2 (Public Review):
The paper describes the participation in CRC screening in Denmark and compliance to colonoscopy in FIT positive screened people during pandemic.
There are interesting data, particularly in the breakdown by age socioeconomic status and immigrant status. Nevertheless, the study remains very descriptive. When a pandemic occurs and different strategies are put in place in different countries to afford this emergency, probably we also need simple descriptions of what happened, considering anything as a natural experiment to be reported. Furthermore, Denmark is one of the few (or the only) European countries that did not stop CRC screening even during the lockdown. Thus it is worth documenting what happened, with a scientific paper. The consequence is that the paper is not very gripping.
The paper is very well …
Reviewer #2 (Public Review):
The paper describes the participation in CRC screening in Denmark and compliance to colonoscopy in FIT positive screened people during pandemic.
There are interesting data, particularly in the breakdown by age socioeconomic status and immigrant status. Nevertheless, the study remains very descriptive. When a pandemic occurs and different strategies are put in place in different countries to afford this emergency, probably we also need simple descriptions of what happened, considering anything as a natural experiment to be reported. Furthermore, Denmark is one of the few (or the only) European countries that did not stop CRC screening even during the lockdown. Thus it is worth documenting what happened, with a scientific paper. The consequence is that the paper is not very gripping.
The paper is very well written and the report is rigorous, the methods well documented, tables and figure clear.
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