Colonoscopies, Blood Tests and the Future of Colorectal Cancer Screening

Mention the word colonoscopy, and many people get a bit uneasy. Yet the colonoscopy is one of our best tools for diagnosing colon cancer, and remains to this day the gold standard.

The first colonoscopy took place in 1969, and yet, years later, it remains an important and effective test. However, persuading those at risk of the disease to undergo this screening can be a challenge. Colonoscopies are invasive and require uncomfortable preparation and often anesthesia. But patients who forgo the procedure for these reasons may be diagnosed later with a more advanced stage of colon cancer. A more advanced cancer means the patient will face tougher treatment options and a worse prognosis.

Nationally, and here at Roswell Park, we're working to develop new, less invasive tests to diagnose colon cancer. My Roswell Park colleague, Dr. Dhyan Chandra, is currently working on collaborative studies with additional scientists at the University at Buffalo. The team is identifying novel biomarkers in the blood that could give us details about how fast or slow colon cancer may be growing in any patient's body, and the specific status of a person's colorectal cancer at any given time.

We believe developing a blood test screening option that is fast, simple and relatively painless, may be the best way to ensure patients are diagnosed at an earlier, more treatable stage, giving them a better chance at long-term survival.

On a related note, just this week, an expert panel at the FDA recommended approving a promising new at-home stool DNA screening test to detect colorectal cancer, the Cologuard test. The test was 92 percent accurate for detecting cancer in the clinical study. This is much better than the current main alternative to colonoscopy, the fecal immunochemical test (FIT), which was 74 percent accurate in the same study.

While we continue our research to create the platinum standard of a highly accurate, non-invasive blood test, the Cologuard test will potentially help more patients and their doctors to find pre-cancerous polyps and cancers earlier. More research is needed to figure out how to use this test most effectively.

It’s important to also realize that until we can create a blood screening that is closer to 95 to 100 percent accurate, no single test will eliminate the need for colonoscopies.

An abnormal test still needs to be followed up with a colonoscopy. Also, for patients at high risk of colorectal cancer, we still recommend screening with colonoscopies as the best way to prevent and detect colon cancer, rather than these other tests.

Still, these advances are exciting. More options may help increase the number of people willing to take that first step toward preventing colorectal cancers, followed by professional medical examinations. And until we have the perfect solution, the colonoscopy will continue to be relied upon.

I encourage you to follow national screening recommendations based on your own particular health history