Caring Currents

Catching Colon Cancer Early Without Colonoscopy

Last updated: Jan 24, 2010

colontest

Researchers unveiled a new blood test this week that they say can detect colon cancer cells early and identify precancerous cells, as well. It's much simpler -- and more comfortable -- than a colonoscopy and will likely be inexpensive, as well. What's the rub? We're not there yet; it still needs more testing.

But the research was big news among colon cancer experts at the American Society of Clinical Oncology (ASCO) Gastrointestinal Cancers Symposium this week. Those of us concerned about colorectal cancer risk need to pay close attention to the future availability of this test and others like it.

Why? Right now the problem with colorectal cancers is that they're silent killers; people usually don't know they have a tumor until they have blood in their stool, at which time they tell their doctor and a colonoscopy is performed. Blood that's present in the stool but isn't visible can be detected with a fecal occult blood test (FOBT).

But many adults don't avail themselves of either of these routine cancer screening tools. Only about half of all Americans ages 50 and older said they'd had a FOBT within the past year or a colonscopy within the past ten years, according to a survey conducted by the CDC. When asked why not, about half of those who hadn't had any tests said they didn't know they should be screened, and the other half said that lack of health insurance and regular health care had prevented them from seeking screening.

The other problem with these tests, beyond the fact that people don't use them, is that they only catch a tumor that's big enough to be causing bleeding or other colorectal cancer symptoms, which also means it's big enough that it could have spread through the intestinal wall or to other organs.

The new test could prove important in preventing colon cancer because it's very easy to do. It's a blood draw that checks the blood for a protein biomarker called CD24 that's elevated when there's a tumor present. Even more exciting, the test proved accurate in identifying polyps that are on their way to becoming cancerous, something that FOBT and colonoscopy can't do. And the researchers said the test could cost as little as $50, which would certainly be a big factor in making it widely available and accessible.

The researchers who identified CD24 and developed the test are at Tel Aviv Souraski Medical Center in Israel, so for now future development of this test will come out of Israel. We'll keep you posted. Researchers in Europe announced this fall that they're working on two other new blood tests designed to determine genetic risk of colon cancer, so look for news on this type of test as well.

In the meantime, what should we be doing to protect ourselves from colon cancer? Make sure you and your family members who are 50 or older are having FOBTs every year and colonoscopies as recommended by your doctor - usually every ten years. However, many doctors are now recommending either a flexible sigmoidoscopy or a virtual colonoscopy every five years instead of a colonoscopy every ten years. If either of these tests detect polyps, then you have the colonoscopy.

Use our checklist to assess your risk of colon cancer and talk to your doctor about which tests you and your family members need.