People who participated in colorectal cancer screening had a 43% lower risk of dying from the disease.
Researchers followed more than 376,000 people in Sweden for up to 14 years.
The findings highlight the potential lifesaving benefits of actually completing a screening test when one is offered.
Colorectal cancer screening may be more powerful than some people realize. New research from researchers at Karolinska Institutet and Umeå University in Sweden suggests that people who participate in screening could have a substantially lower risk of dying from colorectal cancer.
The study looked at Sweden’s Stockholm–Gotland screening program, where adults ages 60 to 74 are offered screening every two years. The process is relatively simple: People receive a kit at home, collect a stool sample, and send it in to be checked for small amounts of blood that aren't visible to the naked eye. If blood is detected, additional testing, usually a colonoscopy, is offered.
“A previous evaluation of the programme showed that those who received an invitation to screening had a 14 per cent lower risk of dying from the disease,” researcher Johannes Blom said in a news release. “We have now been able to show that the mortality is significantly lower than that among those who actually take part in the screening.”
How researchers studied screening
Researchers examined people who were invited to participate in the Stockholm–Gotland screening program between 2008 and 2012. They compared this group with a control group made up of people who were either invited to screening later or weren't invited during the study period.
Because not everyone who receives an invitation actually completes the test, the researchers used statistical methods to account for factors that could affect the comparison. This included accounting for people in the control group who were eventually offered screening and people who received an invitation but chose not to participate.
The study ultimately included 376,511 people, and researchers tracked participants for as long as 14 years. During that time, 1,668 colorectal cancer deaths were recorded.
The results could encourage more people to get screened
The researchers found that simply being invited to screening was associated with a 26% lower risk of dying from colorectal cancer. But the difference was even larger among people who actually participated: Their risk of dying from the disease was 43% lower.
That distinction is important because roughly one-third of people offered screening in the program did not submit a sample.
“Although screening is offered free of charge and the test is simple to carry out, around a third of people do not submit a sample,” Blom said. “Our study highlights the importance of taking part in colorectal cancer screening, and shows that it can actually save lives.”
The researchers note that their findings rely on statistical adjustments, so some uncertainty remains. Still, the results suggest that participating in colorectal cancer screening could make a meaningful difference in the risk of dying from the disease.
For consumers, the takeaway is fairly straightforward: If you're offered a colorectal cancer screening test, completing it may be an important step toward detecting potential problems and reducing the risk of dying from colorectal cancer.