Health Team

Study suggests how often you should get a colonoscopy

Posted September 17, 2008 5:10 p.m. EDT
Updated September 18, 2008 6:41 p.m. EDT

— Only half of Americans who should get screened for colon cancer actually do it. However, a new study may be reassuring to those who do go in for screening and wonder how long before they have to do it again.

Colonoscopy is beneficial because doctors can easily remove anything they find if it could become cancer. The procedure requires 24 hours of medication to cleanse the colon, mild sedation for the exam itself and about a day away from work.

However, a new study published in the New England Journal of Medicine and co-authored by Dr. David Ransohoff of UNC Hospitals, has good news for those who endure it with no sign of cancer.

“They can wait five years before the next exam and maybe even 10 years,” Dr. Robert Sandler, a UNC gastroenterologist, said.

Sandler said that if an abnormality is found and removed, the patient needs another exam in three to five years, depending on the number or size of polyps found.

Researchers found men were more likely than women to develop polyps or advanced pre-cancerous polyps.

Another study published in the New England Journal of Medicine looked at an easier option to colonoscopy. The study cited CT colonography as a fairly effective screening option that identifies 90 percent of polyps or cancers if they are 10 millimeters or larger. It turns X-ray images into a computer generated "virtual colonoscopy," but it may miss small polyps.

“The second limitation of the CT is that it may miss flat polyps, which some people think are more dangerous,” Sandler said.

CT colonography also delivers a small dose of radiation.

If it reveals a polyp, you need to get a colonoscopy to remove it.

People should consider getting screened for colon cancer if their bowel habits change or you notice blood in your stool. If you have persistent abdominal pain, a doctor may also recommend a colonoscopy.

Generally, doctors recommend people aged 50 or older begin regular colon cancer screening. People with a higher risk of colon cancer may need more frequent colonoscopies – maybe even earlier than age 50 – depending on their doctor's advice.