Useful new colon screens don't beat scope

Less-invasive tests may get reluctant patients screened

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PITTSBURGH — Of all of life's necessary indignities, perhaps none is more dreaded — and avoided — than a colonoscopy to screen for early signs of colorectal cancer, the second-most-common cancer-related cause of death in the U.S.

It doesn't have to be, because colon cancers can be caught early -- but many people are reluctant to undergo a time-consuming colonoscopy, which requires a day of cleansing the bowels and then, under partial anesthesia, submitting to a tube, called a colonoscope, that is moved up through the large intestine.

Researchers have been working to come up with alternatives, but even two new screening procedures won't serve as a viable substitute for the time-tested colonoscopy, which has a 98 percent success rate at detecting cancer, according to two Pittsburgh experts.

First, the Food and Drug Administration recently approved a new method of "capsule colonoscopy," using a camera inside a capsule that a patient swallows. It then moves through the entire colon, taking pictures that are uploaded to a computer for medical staff to examine for abnormalities.

Second, a new study says an at-home, mail-in test can use a stool sample to detect up to 79 percent of colon cancers.

Paul Lebovitz, a gastroenterologist at Allegheny General West Penn Health System, is skeptical about the "capsule cameras."

For example, they are "is not directive. When you use a regular camera probe, you can stop, take a picture, or go back and look closely. The camera capsule is a lot less invasive, and that's a benefit, but it's unlikely to be as sensitive."

And if the camera does pick up on something, the patient must then come back anyway for a colonoscopy and biopsy to have the growth — called a polyp — removed. Almost all colorectal cancers begin as a small polyp, and if found and removed early, the cancer is eliminated.

What of the new stool sample test, known as a fecal immunochemical test or FIT? It detects DNA mutations with antibodies that bind the blood in a patient's stool. A study published in the Annals of Internal Medicine found that those tests detected colorectal cancer 79 percent of the time with a single sample. A previous test, the fecal occult blood test, was far less sensitive and required three consecutive samples.

Still, while the FIT has picked up cancers 79 percent of the time, "what about the other 21 percent?" asked Lebovitz, noting that other screenings now available include CAT scans, flexible sigmoidoscopies — which survey less terrain — and virtual colonography, which uses computers and X-rays to look inside the bowels.

However, "Anything we can do," he said, "to draw people into any of the modalities of screening is well worth it."