More cases of colorectal cancer are detected at an early stage with screening, according to a randomised clinical trial by researchers at Uppsala University and Karolinska Institutet. The study has been published in Nature Medicine.
Cancer of the colon and rectum, known as colorectal cancer, is one of the most common cancers. The new study has investigated how beneficial two different screening methods are for detecting cases of colorectal cancer at an early stage. The research is part of the Swedish study SCREESCO, which started in 2014.
Early detection is crucial
The study involved over 278,000 60-year-olds who were randomly offered either a primary colonoscopy; two faecal immunochemical tests (FIT), where the patients provided a stool sample, which was followed by a colonoscopy if at least one of the samples was positive; or no intervention at all (control group).
"The results show that both types of screening lead to more cases of early-stage cancer being detected, especially in the first two years when most of the interventions were carried out. This is good news because, more often than not, cancer that is diagnosed early can be successfully treated. For many types of cancers, there is no preventive treatment option, but in this case, it is also possible to detect and remove adenoma - precursors that might otherwise have developed into cancer," says Marcus Westerberg, docent at the Department of Surgical Sciences, Uppsala University and the study's corresponding author.
Best results with faecal samples
In patients where the precursors to cancer were found in a colonoscopy, they received treatment according to the current guidelines. The participants were then followed via the register until 2020.
At the end of the follow-up period, the researchers found that the number of cases of more advanced colorectal cancer had decreased in both intervention groups. The clearest results were seen in the group where the participants had done FITs. There, 0.61 per cent developed colorectal cancer, compared to 0.73 per cent in the control group.
"We can show that cases of advanced cancer tend to decrease towards the end of the period in the group that was randomised to provide stool samples for FIT. This could be evidence of a preventive effect of the screening, through the removal of the precursors to cancer," says Anna Forsberg , docent at the Department of Medicine, Solna , Karolinska Institutet, who is the last author and responsible for SCREESCO.
Participants are followed until 2030
The researchers also investigated whether there were any negative effects associated with an increased number of colonoscopies. They noticed a slight increase in stomach and intestinal bleeding as well as blood clots, especially in the first year when most of the colonoscopies were performed. However, these events were unusual, and the all-cause mortality rate was the same in all groups.
The participants will now be followed until 2030 to see how effective the different screening methods are in reducing long-term mortality from colorectal cancer.
"This study gives us great hope that screening will also be shown to reduce mortality from colorectal cancer in both groups when the study is finally evaluated in about five years," says Anna Forsberg.
This news article is based on a press release from Uppsala University.
Publication:
"Colonoscopy and fecal immunochemical testing versus usual care in diagnostic colorectal cancer screening: the SCREESCO randomized controlled trial" , Marcus Westerberg, Jonas F. Ludvigsson, Chris Metcalfe, Ulf Strömberg, Johannes Blom, Lars Engstrand, Mikael Hellström, Christian Löwbeer, Robert Steele, Lars Holmberg, Anna Forsberg, Nature Medicine, online 20 February 2026, doi: 10.1038/s41591-026-04225-9.
Facts in brief
In Sweden, a national screening programme started being rolled out in 2021 with full implementation planned for 2026. The screening is offered every two years to individuals aged 60-74 years and is based on a faecal immunochemical test (FIT) followed by a colonoscopy if the sample is positive. The cutoff values for a positive FIT are 40 μg Hb per gram of stool for women and 80 μg Hb/gr for men.
The study SCREESCO compares no intervention with screening with once-only colonoscopy and screening with two rounds of two-stool FIT, with a low cutoff for a positive FIT of 10 μg Hb/gr for both men and women.
