Colonoscopies Could Reduce Cancer Risk By 40 Percent
A colonoscopy every 10 years could prevent 40 percent of colorectal cancers, a US study finds.
Those with a family history of these types of cancer should have more frequent screenings, the study in New England Journal of Medicine said. Colorectal cancers are the second-leading cause of cancer deaths in the US.
The results also confirm that current recommendations for colonoscopies is particularly useful in preventing cancers that originate in the proximal, or upper part of the colon.
“Our study provides strong evidence that colonoscopy is an effective technique for preventing cancers of both distal and proximal regions of the colorectum,” said Shuji Ogino, a lead author from the Havard School of Public Health.
"The screening is crucial in preventing proximal cancers, he explained, because another test, called sigmoidoscopy, uses a scope to examine only the lower part of the colon and “alone is insufficient for preventing proximal cancer,” he also added.
A colonoscopy examines the entire colon, using a camera-equipped device that also has tools to remove cysts and benign tumors.
“This study provides some of the clearest evidence to date that colonoscopy has advantages over sigmoidoscopy for the prevention of colorectal cancer, although it is not a perfect test,” said Andrew Chan, one of the senior authors of the paper and associate professor of medicine at Harvard Medical School.
The researchers analysed data from nearly 89,000 participants in two long-term studies. They based their conclusions on surveys completed every two years between 1988 and 2008.
They concluded that, if all the participants had undergone a colonoscopy, the overall risk of colorectal cancers would have been reduced by 40 percent. It would have prevented 61 percent of lower colon cancers and just 22 percent of upper colon cancers.
Researchers speculated that the variance in the success rates might be the result of molecular or biological differences between upper and lower colon cancers.