Advances in laboratory based testing could provide an additional tool to identify people at increased risk for colorectal cancer so the disease can be prevented and/or caught at an early stage.

Colorectal cancer is the third most common cancer and the second most common cause of death from cancer for both Canadian men and women.  While colorectal cancer is highly treatable when detected early and is up to 90 percent preventable with timely and thorough screening and testing, as it stands today, nearly half of those diagnosed find out too late.

Population-based screening programs

Early detection of cancer and precancerous growth is key to improving survival rates.

To this end, many provinces have put in place population-based colorectal cancer screening programs.  Most provinces recommend that for people at average risk, they should get screened for colorectal cancer every two years, starting at the age of 50.  Screening tests involve a stool-based test such as ‘The Fecal Occult Blood Test’ (FOBT) or ‘Fecal Immunochemical Test’ (FIT) that the person can perform at home.

“If you’re one of those people who has been avoiding getting tested, make today the day that you pick up the phone and book your appointment.”

“The patient collects stool samples putting a little bit of stool on a card (FOBT) or tube (FIT) provided by their physician, and then mail it back to a lab,” explains Dr. Tim Feltis, the Deputy Ontario Medical Director for LifeLabs. “A chemical reaction test is then performed on that sample in order to detect small amounts of blood in the stool.”  Where blood is detected in these tests, follow-up tests (typically a colonoscopy) are performed to determine if it is due to the existence of colorectal cancer.

A particular challenge that provinces are facing is getting people to participate in the screening recommendations.  For various reasons, colorectal cancer screening rates are well below the levels needed to be as effective as possible at early detection.  Some have suggested that people can’t get over their discomfort with the stool-based samples.

Making breakthroughs

In response to the general reluctance of patients to handle stool samples, scientists have developed a blood testing technique that can accurately identify patients at increased risk of getting colorectal cancer.

“The development of Cologic blood testing for the identification of patients at increased risk for colorectal cancer is yet another tool that can help us improve the rate of early detection,” said Dr. Feltis. “This test has a low false negative rate and an acceptable false positive rate, meaning it is very accurate at detecting risk and therefore can facilitate early detection of premalignant/malignant lesions resulting in better outcomes.”

By measuring the level of an anti-inflammatory long chain fatty acid, GTA-446, in the blood, the test determines whether or not a patient is at risk for colorectal cancer. “It’s a simple blood test, there’s no need to collect a stool sample,” says Dr. Feltis. “If your cologic level comes back low, you are at risk. There was a large study done showing that 86 percent of people with cancers have low levels of GTA-446.”

This simple blood test can determine a patient’s risk factor long before the cancer has even started to develop.  

A new alternative

The Cologic test is a new alternative that can be used on its own or as a precursor to a stool-based screening program.  Dr. Feltis believes that the introduction of easier, less invasive testing methods will lead more people to comply with regular testing, which is currently a major barrier in the fight against colorectal cancer.

If you’re one of those people who have been avoiding getting tested, make today the day that you pick up the phone and book your appointment. “The message is simple,” says Dr. Feltis, “for those with a family history, change in bowel habit - at any age - or over 50 years of age, just get tested, it’s not as bad as you fear.”