New Developments in GI Testing

with Drew Elgin, M.D., gastroenterologist, Columbia St. Mary’s

Last Updated: June 1, 2003

One of the reasons that colon cancer and other serious gastrointestinal disorders are sometimes caught late in their development is due to the screening tests available, which some people may avoid due to concerns about pain, risks or inconvenience.

Recently, new tests were approved, or are about to be, for stomach and intestinal screening. Some of the newest and most promising already are available at Columbia St. Mary’s. These include new endoscopic examining tools and advanced forms of imaging and genetic testing.

Drew Elgin, M.D., gastroenterologist, Columbia St. Mary's "These tests are not additive tests. Instead they offer new ways to pick up a problem quicker and easier. You reach the diagnosis more rapidly and less painfully for the patient."

Capsule endoscopy
For years physicians have examined the esophagus and stomach with little lights and cameras on the tip of thin, flexible tubes. Now there’s a little chip implanted in a tiny capsule, about twice the size of a Tylenol pill, which travels through the digestive tract, taking two pictures every second.

“The advantage to the patient is that there is no need for any sedation and it can be done on an outpatient basis. It allows us to look at the small intestine, primarily to look for intestinal bleeding or pick up problems like Crohn’s disease and small bowel tumors that cannot be diagnosed by other tests available. It is particularly helpful in cases where diagnosis is not clear,” said Dr. Drew Elgin, a gastroenterologist with Columbia St. Mary’s.

However, the device has some limitations. According to Dr. Elgin, the device takes good images of the stomach and small intestine but since the battery only lasts about six hours the imaging is limited to those organs and does not visualize the colon. “The other downside is that you cannot treat problems if you find them,” Dr. Elgin added. However, future refinements may allow for longer battery life and some treatment via the device.

Endoscopic ultrasound
Only a few years old, endoscopic ultrasound has aided physicians in diagnosing pancreatic, gastric and esophageal cancers and for staging cancers. “Staging determines what level a cancer is at. How deeply penetrated it may be. Success in treatment of cancer depends on this,” Dr. Elgin said.

This type of ultrasound is done via an endoscope, taking an ultrasound image from inside the body. The procedure does require some sedation. However, like regular endoscopy, it also allows some treatment. “You can take biopsies, inject chemicals and drain cysts. For example, in the past if a cyst on the pancreas needed to be drained, we would stick a tube through the abdominal wall. Now we can drain them internally into the stomach, saving the patient surgery and time in a hospital,” Dr. Elgin said.

CT colonography
CT (computerized tomography) colography is a CT scan done on the colon or abdomen. It requires the same prep as for a colonoscopy but requires no sedation. It can pick up many major problems of the colon. However, like the capsule endoscopy, it cannot treat any problem that might be found. “At the present time we use it for those at high risk for any sort of invasive procedure; elderly patients who cannot tolerate sedation, those with cardiac problems, those on blood thinners,” Dr. Elgin said.

PET scan
Positron emission tomography (PET) was developed after researchers learned that cancer cells metabolize fuel more quickly than normal ones. A PET scan requires no fasting or other preparation by the patient. The patient is given a glucose injection, then the scanner reads through the skin looking for abnormal hot spots in the body. “Other scans visualize abnormal tissues. This scan visualizes the abnormal metabolisms that tumor tissues have,” the doctor said.

The PET scan also is used to diagnose breast cancer.

Genetic testing
Since GI tests are often invasive, require fasting and often a cleansing of the area to be examined, the most promising new developments in testing are genetic ones. New tests are being developed to determine who is at risk for hemochromatosis, a common hereditary disease that causes cirrhosis of the liver, for Crohn’s disease and for lactose intolerance. These tests may make diagnosis easier, faster and more accurate.

Currently physicians can test for rare, but dangerous, hereditary colon cancer syndromes. Those who carry a gene for this develop numerous polyps in the colon and often these become cancerous by the time this person reaches the mid-30s. Since most colon cancers do not occur until a person is in his 50s, it is important to diagnose this condition and frequently examine those who have it. The genetic test allows physicians to determine which family members have inherited the defect and which can be spared invasive and frequent testing.

“We had a patient who had a polyposis syndrome and came into Columbia Hospital with colon cancer. He was a young guy, about thirty-five, and carried the gene. We tested his two young sons. One carries the gene. The other does not. The one who carries it will be followed so he doesn’t get colon cancer as he ages. The other boy who doesn’t carry the gene will not need to undergo frequent endoscopic exams for the rest of his life,” Dr. Elgin said.

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