The team evaluated the reduction in mortality from colorectal cancer (CRC) by repeated screening with fecal occult blood tests.
They published their findings in the January 2002 issue of Gut.
A total of 137,485 residents of Funen, Denmark, aged 45-75 years were included in the study population. In 1985, 30,967 of these subjects were randomly allocated to biennial screening with Hemoccult-II and 30,966 were allocated to the control group.
Only participants who completed the first screening round were invited for further screening. Colonoscopy was offered if the test was positive.
The primary end point was death from CRC, and the 10-year results were published in 1996. A total of 7 screening rounds were conducted.
From the beginning of the first screening to the seventh round, mean age increased from 59.8 to 70.0 years in the screening and control groups, and the male/female ratio decreased from 0.92 to 0.81.
Those who accepted screening were found to be younger than non-responders.
Positivity rates varied from 0.8% to 3.8%, and the cumulative ratio of a positive test was 5.1% after 7 rounds.
| After 7 screening rounds, RR was less than 0.7.
Some 4.8% of patients had at least one colonoscopy.
The researchers found that mortality from CRC was significantly less in the screening group (relative risk [RR] 0.82). In addition, the reduction in mortality was most pronounced above the sigmoid colon.
After 7 rounds, RR was reduced to less than 0.70, compared with controls.
Mortality rates from causes other than CRC did not differ.
Non-responders had a significantly increased risk of death from CRC compared with those who accepted the full program.
Furthermore, subjects who accepted the first screening, but not subsequent ones, demonstrated a tendency towards increased risk.
Author O. D. Jørgensen, of the Odense University Hospital, said on behalf of colleagues, "The persistent reduction in mortality from CRC in a biennial screening program with Hemoccult-II support attempts to introduce larger scale population screening programs. This is also supported by the reduction in relative risk to less than 0.70 in those adhering to the program.
"The smaller effect on mortality from CRC in the rectum and sigmoid colon suggests evaluation by additional flexible sigmoidoscopy with longer intervals," it was concluded.