Sept. 30, 2004 -- Only close to half of men and women over 50 have ever had one of the two most effective tests to detect colorectal cancer, colonoscopy or sigmoidoscopy, and less than a quarter have had one within the last five years as recommended to screen for the disease, new researcher shows.
Colorectal cancer is the third leading cause of death in the U.S. Several screening methods are available to check for signs of the disease, but recent research has shown that colonoscopy and sigmoidoscopy are more effective in catching cancers in the colon and rectum during the early stages and thus reducing the risk of death due to the disease.
Both methods involve inserting a thin, lighted tube through the anus to view the colon. Some people find the procedures embarrassing and painful.
During a signmoidoscopy, a doctor may view only the lower third of the colon through the flexible tube. But in a colonoscopy, a small video camera is attached to the tube that allows the doctor to view the entire colon.
Researchers say the results show that screening tests for colorectal cancer are underused, even among a health conscious population.
"This is remarkable since screening guidelines have been widely published and flexible sigmoidoscopy and colonoscopy have been proven to be effective in reducing colorectal cancer mortality," says researcher Michael Thun, MD, of the American Cancer Society, in a news release. "This is a clear example of how the burden of this cancer could be reduced just by applying what we already know."
Adults Lax About Colorectal Cancer Screening
In the study, researchers analyzed data collected in 1997 from more than 184,000 men and women aged 50-74 who were participants in a major cancer prevention study and considered more health conscious than most other adults. The results appear in the October issue of the American Journal of Public Health.
Overall, 58% of men and 51% of women said they had ever undergone a colonoscopy or sigmoidoscopy, but only 35% had one within the last five years, as recommended by major health organizations.
In addition, researchers found only 42% of men and 31% of women had undergone the tests as a screening method for colorectal cancer rather than for disease diagnosis or follow-up.
The study showed that several demographic and lifestyle factors were linked to lower use of colonoscopy and sigmoidoscopy, including:
- Women, who usually are more likely to take advantage of preventive care measures, were less likely that men to use either screening method
- Younger age (50-64)
- Not having health insurance
Other factors, which are known to increase the risk of colorectal cancer, were also associated with lower screening rates, such as:
- Overweight or obesity
- Physical inactivity
- Being a smoker
Colorectal Cancer Screening Guidelines
The American Cancer Society recommends the following colorectal cancer screening guidelines for men and women who are at average risk for developing colorectal cancer, such as those without a family history of the disease.
Starting at age 50, men and women should follow one of the five screening options below:
- A fecal occult blood test (FOBT) every year, or*
- Flexible sigmoidoscopy every five years, or
- A fecal occult blood test every year plus flexible sigmoidoscopy every five years, or*
(Of these first three options, the combination of FOBT every year and flexible sigmoidoscopy every five years is preferable.)
- Double-contrast barium enema every five years, or
- Colonoscopy every 10 years
*For FOBT, the take-home multiple sample method should be used.