Colorectal Cancer Archive

A colonoscopy can help prevent the diagnosis of late-stage colon cancer. Research suggests that the test can reduce the likelihood of advanced colorectal cancer diagnosis by 70% in adults with average risk.

There's more than one effective way to screen for colon cancer, according to researchers at Harvard-affiliated Massachusetts General Hospital. After a negative colonoscopy at age 50, getting rescreened annually with a less invasive fecal occult blood test or fecal immunochemical test, or having a computed tomographic colonography (virtual colonoscopy) every five years is about as accurate as having another colonoscopy every 10 years, but is less expensive and less likely to cause complications.

Screening by any method significantly reduces the risk of colon cancer compared with not screening, found the Annals of Internal Medicine study, which used a simulation model to identify differences in colon cancer detection among the various testing methods. Colonoscopy every 10 years leads to the fewest colorectal cancer cases and deaths, but it also has the highest complication rate and is the costliest testing method. Although an accompanying editorial cautions that the simulation models used in this study can be "imprecise," the findings reinforce the idea that any colon cancer test is better than no test. Current guidelines recommend that women ages 50 to 75 get a colonoscopy every 10 years; a flexible sigmoidoscopy, double-contrast barium enema, or CT colonography every five years; or a fecal occult blood test or fecal immunochemical test every year. Talk with your doctor about which testing method is most appropriate for you.

It appears that colon cancer patients whose tumors have a mutated form of the PIK3CA gene may live longer if they take aspirin. Aspirin may also help fight other kinds of cancers and protect heart health.

Back in 2009, Dr. Andrew T. Chan and his colleagues at Harvard-affiliated Massachusetts General Hospital found that people diagnosed with colorectal cancer who took aspirin on a regular basis tended to live longer than those who didn’t take aspirin. Aspirin worked only for some people, though, so Chan and a larger team of researchers set out to learn why. Their latest work, published in the New England Journal of Medicine, indicates that people with colorectal cancer who have a mutation in a gene called PIK3CA are most likely to benefit from aspirin. (About 15% to 20% of people with colorectal cancer have this gene mutation.) The mutation permits colon cancer cells to thrive. Aspirin blocks this action. If confirmed, this work could lead to routine genetic testing for people with this common cancer, and aspirin therapy for those with the PIK3CA mutation.

A huge new study has identified many new genetic changes that appear to be involved in causing colorectal cancer. Each of these newly identified genetic changes is a target for drug therapy.

Learn which colorectal cancer tests you need, and how often you need them.

Harvard Women's Health Watch presents the first in our series of guides to help you make smarter choices about screening tests. This article will focus on colorectal cancer screening, with advice from Dr. Robert Mayer, the Stephen B. Kay Family professor of medicine at Harvard Medical School.

Findings from a large clinical trial reported in The New England Journal of Medicine add to previous evidence that undergoing a flexible sigmoidoscopy every three to five years reduces the risk of developing colorectal cancer later in life. This is important because sigmoidoscopy is less invasive and easier to prep for than full colonoscopy, which uses a longer instrument to examine the entire colon. Some people might choose to undergo sigmoidoscopy who might otherwise avoid screening.

"Sigmoidoscopy has fewer complications, easier prep and no sedation," says Dr. William Kormos, editor in chief of Harvard Men's Health Watch. "It is reasonable start for people at average risk."

An experimental approach to virtual colonoscopy could eliminate the unpleasant day-before bowel prep that keeps many people from having this potentially life-saving test. Virtual colonoscopy uses computed tomography (CT) scanning with X-rays, instead of a scope, to check the colon for cancers and precancerous polyps. Earlier version have required bowel cleaning, just like regular colonoscopy. A Harvard-based team led by Dr. Michael Zalis uses sophisticated computer software to make stool in the colon disappear. It’s a little like Photoshopping blemishes from still photos. “Laxative-free CT colonography has the potential to reach some of the unscreened population and save lives,” says Dr. Zalis, an associate professor of radiology at MGH and director of CT colonography at MGH Imaging.

Worse than the colonoscopy itself? Probably. Here's how to make this unpleasant but essential task go more smoothly.

If you shudder at the thought of having a colon cancer–screening colonoscopy, chances are it's the "prep" that's stoking your apprehension. It's certainly a major inconvenience: getting ready for the procedure takes much longer — according to one study, 16.5 hours, on average — than the time you'll spend at a medical center the day of your colonoscopy (usually no more than three hours). But what's most off-putting is the purgative part — taking a powerful bowel-clearing substance and coping with the resulting diarrhea.