A new test for colon cancer screening

A group of Canadian researchers recently reported that they have developed a test by which "molecular traces" of the presence of precancerous colon polyps can be found in the blood. If the results of the study are confirmed, a sensitive, specific, inexpensive and absolutely noninvasive screening test for colon cancer will be available to complement the more traditional and invasive colonoscopy.

It is thanks to the latter that today we are able to diagnose and treat colon cancer early, or even prevent it, by removing during the examination those precancerous lesions-the polyps-from whose evolution the cancer itself may originate.

However, colonoscopy is an expensive and unpleasant test for patients; preparation of the colon with powerful laxatives is required in the days before the examination, and the patient must undergo sedation or anesthesia in order to tolerate it. Current screening programs call for colonoscopy to be performed starting at age 50, or earlier if you have a family history of colon cancer; however, since it is a less than "pleasant" exam, there are many people who decide not to have it. That's why numerous research groups around the world are scrambling to develop less invasive screening tests.

Working along these lines, researchers from the BC Cancer Agency and the University of British Columbia have found that there are differences between the blood of patients with precancerous polyps and that of healthy patients; and the blood chemistry test they developed is based on these findings.

Specifically, the results of a previous study were taken up, whereby differences in the Raman spectrum of blood from healthy patients compared with blood from colon cancer patients were demonstrated. The new research showed that spectroscopic differences also exist between the blood of patients with precancerous polyps compared with that of healthy patients, and that this can be applied in the clinic in screening programs.

It must be clear: no blood test will ever come to replace colonoscopy, which will still have to be carried out at the slightest suspicion of the presence of polyps; but it will certainly be easier to expand the pool of people undergoing screening programs. Today, colon cancer is a disease from which one can be cured: one only needs to identify and treat it in time.