MONDAY, May 13, 2002 (HealthDayNews) -- If you're at high risk for colon cancer, do you know how often you should get screened for the disease?
New research says that people with a history of polyps, which are pre-cancerous growths, should have a colonoscopy every three years. People who have colon cancer in their family can go five years between screenings if their first colonoscopy turns up negative.
"We prove that when these recommendations were followed, nobody has gotten cancer," says Dr. David Beck, study author and chairman of the Ochsner Clinic Foundation's Department of Colon and Rectal Surgery in New Orleans.
The study will be presented at the American Society of Colon and Rectal Surgeons' annual meeting in Chicago next month.
Beck and his colleagues followed 832 people with a family history of colon cancer who received colonoscopies from 1981 to 2001 at varying intervals. The average age of the patient was 59. A colonoscopy, which takes about an hour, is an examination of the rectum and the entire colon with a lighted instrument.
About one-third of the study participants had at least one polyp at the time of their first screening. Of that group, 22 percent had developed additional polyps three years after the initial colonoscopy. Five years later, 48 percent had.
In contrast, among the two-thirds of people who had no polyps at the time of their first colonoscopy, only 3 percent had developed polyps three years later. Five years later, 13 percent had.
Nobody developed colon cancer during the study, Beck says.
"Those that had polyps on the first exam were much more likely to have polyps on the second exam," he says. "But if the first exam is normal, you can wait five years."
The study also found that women's polyps grew more slowly than men's, but more research is needed before making gender-based recommendations, Beck says.
The Ochsner Clinic's recommendations are almost identical to what the American Cancer Society has urged for years, says Dr. Durado Brooks, director of prostate and colorectal cancers for the society.
"The major findings of this study simply confirm earlier work regarding the natural history of polyp development and progression," Brooks says.
Colorectal cancer, which strikes the colon or the rectum, is the second leading cause of cancer deaths among men and women in the United States. This year, an estimated 150,000 people will be diagnosed with the disease and 57,000 will die from it, according to the National Cancer Institute.
"Previously, we had picked numbers for screening intervals but nobody had data to support it," Beck says. "With our data, we now have some proof to support those recommendations."
Age is a major risk factor for colorectal cancer. Other risk factors include a diet low in fruits and vegetables and high in animal fat; a family or personal history of colorectal polyps or cancer; obesity; excessive alcohol consumption; cigarette smoking; and inflammatory bowel disease.
When caught early, colorectal cancer is highly treatable. Polyps are essentially the body's early warning system, Beck says.
The American Cancer Society recommends everyone over the age of 50 get screened for colon cancer with a colonoscopy every 10 years. People at high risk of the disease should get screened as early as puberty.
There are three other screening tests for colon cancer your doctor may recommend: a fecal occult blood test, which tests for hidden blood in the stool; a sigmoidoscopy, an examination of the rectum and the lower colon with a flexible light instrument; or a double contrast barium enema, a series of X-rays of the colon and rectum.
What To Do
Go here for details on the American Cancer Society's screening guidelines. For more information about a colonoscopy, visit the American Society of Colon and Rectal Surgeons.
