FRIDAY, July 1, 2011 (HealthDay News) -- It may sound simple: Colorectal cancer is generally considered one of the most preventable types of cancer that people can develop. So get screened and prevent it.
But the devil is in the details. Cancer experts have found much confusion regarding the guidelines for when and how people should be screened for colon cancer.
A precise colorectal cancer screening can locate pre-cancerous polyps within the colon. Polyps can be removed and, once gone, their potential to cause colon cancer is gone, too.
However, a study released last fall by the U.S. Centers for Disease Control and Prevention found that only one in five doctors in the United States follow all recommended colon cancer screening guidelines. Most correctly recommend that screening begin at age 50, but they're inconsistent in describing the screening options and how often they should be utilized, the CDC reported.
"We have made some progress getting physicians on board with screening, but now we need to make sure they know which tests work, which tests don't work, and that there can be too-frequent testing," said Dr. Durado Brooks, director of prostate and colorectal cancers for the American Cancer Society.
The result has been a lot of head-scratching among patients, cancer experts say.
"I work a lot with the public, and there's definitely unfamiliarity with what age to begin getting screened, and which screening tool to use," said Suzette Smith, the Prevent Cancer Foundation's director of partnerships for colorectal cancer screening.
About 142,570 new cases of colorectal cancer were reported in 2010, according to the U.S. National Cancer Institute, and about 51,370 people died from the disease.
Most of those deaths could have been prevented through screening, the CDC maintains, but nearly half of all colorectal cancers are not detected until they've reached a late stage, according to the agency.
Part of the problem involves a lack of awareness, Brooks said. "There are a number of different tests available for screening, and patients need to be made aware of their options so they can take the test they are comfortable with," he said.
Colonoscopy has long been regarded as the "gold standard" for colon cancer screening, Smith said. And with good reason: It is a very thorough test, and doctors can remove any polyps as they find them without making people undergo a second procedure.
But some people remain reluctant to have a colonoscopy, Brooks said. Again, with good reason: Preparing for a colonoscopy can be quite unpleasant, and it is an invasive procedure that requires sedation and comes with some risk, though small.
"It's not a procedure you want people to go through if they don't need to have the test," Brooks said. "On the other hand, colonoscopy is the test that needs to be performed if any of the other tests come back abnormal."
The CDC's recommendations for colon cancer screening actually call for a mix of screening tests. Starting at age 50, the agency says, people should receive:
- A high-sensitivity fecal occult blood test every year. This test checks for hidden blood in stool samples. "Those tests have been shown to decrease the chance of developing and dying from colon cancer," Brooks said.
- A flexible sigmoidoscopy every five years. In this test, physicians use a flexible, lighted tube to visually inspect the interior walls of the rectum and part of the colon. It's a shorter tube, so the screening covers only the lower third of the colon. "That's where the majority of cancers start, so it is a fairly effective test," Brooks said.
- A colonoscopy every 10 years. The longer tube, also flexible and lighted, used in this test is capable of examining the entire length of the colon. Physicians also can send instruments down through the tube to collect biopsies or remove polyps.
The American Cancer Society recommends other screening options. For instance, people could have either a barium enema or a virtual colonoscopy every five years in lieu of a flexible sigmoidoscopy, if they so chose.
Virtual colonoscopy is the most recent screening test to be developed for colon cancer. It involves the use of CT scans to inspect the lining of the colon. And virtual colonoscopy has grown in credibility in recent years.
"There have been now enough large studies in multiple settings to show that virtual colonoscopy is almost as good as traditional colonoscopy in detecting cancers, and it also does a good job at detecting large polyps," Brooks said.
But there are downsides, Smith said. People undergoing virtual colonoscopy have to endure the same unpleasant preparation rituals used for regular colonoscopy. And, if anything is found, they will have to have a regular colonoscopy for further examination and treatment.
One more thing people should keep in mind, she said: Everyone -- not just men -- should be screened for colon cancer.
"A popular misconception is that colon cancer affects only men, when it affects men and women at equal rates," Smith said.
The American Cancer Society has more about colorectal cancer.
A companion article looks at one state's effort to improve its dire statistics on colorectal cancer.
SOURCES: Durado Brooks, M.D., M.P.H., director, prostate and colorectal cancers, American Cancer Society; Suzette Smith, director, Partnerships for Colorectal Cancer Screening, Prevent Cancer Foundation; Oct. 14, 2010, Journal of General Internal Medicine, online; Nov. 24, 2010, U.S. Centers for Disease Control and Prevention, Surveillance of Screening-Detected Cancers (Colon and Rectum, Breast, and Cervix) United States, 2004-2006
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