People who have a screening colonoscopy may reduce their risk of developing colorectal cancer by about 40 to 50 percent, according to an international study led by Prof. Michał Kamiński of the Maria Skłodowska-Curie National Research Institute of Oncology.
The findings were published in The Lancet, one of the world’s leading medical journals.
The study followed nearly 85,000 people aged 55 to 64 over 13 years. Participants were randomly assigned either to receive an invitation for screening colonoscopy or to remain under observation. The study began in 2008 and examined both new cases of colorectal cancer and deaths from the disease.
“Our goal was to verify whether an invitation to screening colonoscopy reduces the risk of illness and death from colorectal cancer,” Kamiński told Poland's PAP news agency. “To assess that and determine the scale of the potential risk reduction, the study had to include a sufficiently large group of people and last long enough.”
In Poland, colorectal cancer screening is available to people aged 50 to 65 who have no symptoms suggesting the disease and have not had a colonoscopy in the past 10 years. People aged 40 to 49 can also be tested if a first-degree relative has been diagnosed with colorectal cancer.
Among all those invited for screening, regardless of whether they actually underwent the test, the risk of developing colorectal cancer was 20 percent lower.
“That is a significant result,” Kamiński said. “If we could avoid 20 percent of cases of this cancer in our society, that would be a lot.”
The effect was far stronger among those who had the colonoscopy. Kamiński said only about 40 percent of those invited actually attended the test, but in that group the risk of developing colorectal cancer fell by around 40 to 50 percent. “That is one of the biggest effects one can expect from preventive measures in oncology,” he said.
Colonoscopy can detect cancer, but it can also identify and remove polyps, growths that may later turn cancerous. Kamiński said polyps can appear several years before colorectal cancer develops. “During the examination, we can easily remove them, which reduces the risk of disease,” he said.
The study’s findings on deaths from colorectal cancer were more complicated. Researchers found no significant difference in mortality between the control group and the group invited for screening.
Kamiński said the result was surprising because it differed from the assumptions made when the study was designed years earlier. He said it was still good news, because cancer treatment has improved substantially over the past two decades, reducing deaths in all the countries covered by the study.
He said early detection still matters from both the patient’s and the health system’s point of view.
“For the patient, it matters whether they avoid cancer or can undergo less invasive treatment because the disease is detected at an early stage,” Kamiński said. “For the system, there is a difference in costs. Preventive testing is much cheaper than cancer treatment, especially at an advanced stage.”
Kamiński said Poland still lacks a fully organized colonoscopy screening system, even though colorectal cancer is a major health risk. He noted that cervical cancer is much less common, but cervical screening is far more widespread.
“There are no invitations, no structure, no organization, many elements are missing, so we cannot say that we have an organized colonoscopy screening program in Poland,” he said.
He added that low participation should not be blamed on the public alone. The health care system and the way people are invited for tests play a major role.
“There are effective and proven methods that greatly increase participation in such preventive programs,” Kamiński said. “There are countries where it reaches 60 percent. That is what we should aim for.”
Data from the National Health Fund (NFZ) show that from the fourth quarter of 2022 to the end of October 2025, 238,000 people took part in screening. Colorectal cancer was detected in 2,153 people, fewer than 1 percent of those examined, including 942 women and 1,211 men.
(rt/gs)
Source: IAR, PAP