A new study supports what gastroenterologists have preached to their patients for decades, having a screening colonoscopy greatly reduces the risk of developing colon cancer. Now they know by how much.
The study, published in the March 5 issue of the Annals of Internal Medicine, found that for average-risk people, screening colonoscopies produced a 70 percent reduction in risk for newly detected cases of advanced-stage colon cancer – the type most difficult to cure.
This study affirms what GI physicians see in our practices every day – that screening colonoscopies save lives through either detection and removal of precancerous polyps or by early diagnosis of colon cancer, which is curable in about 90 percent of cases if detected before symptoms develop.
The National Institutes of Health’s (NIH) National Cancer Institute estimates that in 2013, about 143,000 cases of colorectal cancer will be diagnosed, resulting in 50,830 deaths.
While colonoscopy is commonly used as a screening test for colon cancer, there existed very little research that proved it is effective in reducing colon cancer deaths, according to the study authors. The researchers sought to answer the question, “If you ended up with late-stage cancer, were you more or less likely to have had a screening colonoscopy as many as 10 years before the disease was discovered?”
The study authors analyzed the health records of more than 1,000 adults age 55 to 85 who were not at high risk for colon cancer. They also wanted to evaluate whether colonoscopy is an effective tool to screen the right side of the colon, which is more difficult to reach and often has pre-cancerous areas that are tougher to spot and identify.
“Colonoscopy has the ability to identify both left- and right-sided colon cancers before they have progressed to an advanced stage,” said lead study author Dr. Chyke Doubeni, associate professor in the department of family medicine at the University of Pennsylvania.
The NIH recommends that people 50 to 75 be screened for colon cancer in one of three ways: a colonoscopy every 10 years, a sigmoidoscopy (in which a scope is used to examine the last part of the colon, the sigmoid) every five years combined with a home fecal occult blood test every three years; or a home fecal occult blood test every year.