New blood test can find colorectal cancer at an early stage

FROM 2008 ORLANDO GI SYMPOSIUM

A new test for a protein found in the blood of patients with colorectal cancer or with advanced polyps may provide a simple way to identify the disease earlier.

Scientists at Johns Hopkins University and the University of Pittsburgh measured levels of colon cancer-specific antigen-2 (CCSA-2) in blood from patients who had undergone colonoscopy.  Patients had either normal colonoscopies, hyperplastic and non-advanced adenomas, advanced adenomas, or colorectal cancer.  Another group of control blood samples were also included.

They found a level of CCSA-2 that was present in over ninety percent of patients with colorectal cancer or an advanced adenoma (a polyp in the colon with high potential to develop into colon cancer).

Only about 20 percent of people without cancer or advanced polyps had the marker in their blood making the test unlikely to find many false positives.

Diagnosing colorectal cancer in its earliest stages would mean more cures and less difficult treatment for patients.  Since the CCSA-2 test also finds advanced polyps before they become cancerous, it might have the ability to prevent the disease entirely.  More sensitive than current stool tests and less invasive than colonoscopy, it might be able to screen for those people who need colonoscopy exams.

The researchers point out that the test needs further validation before it can be proven effective for colorectal cancer screening.

Robert Getzenberg and his team reported to the 2008 GI Symposium in Orlando that,

Although further validation studies are required, our initial study demonstrates that CCSA-2 is a potential serum-based marker for colon cancer detections with high sensitivity and specificity.

SOURCE: R. H. Getzenberg, Initial evaluation of colon cancer-specific antigen-2 (CCSA-2) as a serum marker for colorectal cancer, 2008 Gastrointestinal Symposium, Abstract Number 276.