Test for Traveler's Diarrhea May Detect Spread of Colorectal Cancer

Researchers at Thomas Jefferson University are beginning a clinical trial to determine whether a simple test for the protein that causes traveler's diarrhea will help provide a more accurate picture of the extent of colorectal cancer in patients.

The scientists say they hope the test will enable them to determine whether or not cancer has spread from the colon to the lymph nodes, resulting in improved diagnoses and more appropriate treatment.

The test looks for evidence of a protein, guanylyl cyclase C, or GCC, which is expressed only by intestinal cells and colorectal cancer cells. Researchers said GCC appears to be very specific to colon cancer cells outside the intestine, and is only expressed in metastatic colon cancer cells that have spread there.

In a previous trial, Dr. Scott Waldman and his team examined 21 colorectal cancer patients. One group of 11 patients had been disease-free for at least six years and deemed "cured." The other group of 10 patients developed recurrent disease within three years after cancer surgery. The latter had been told initially that they had no signs of cancer in their lymph nodes after surgery, meaning their cancer had not spread.

When pathologists examined lymph node samples of each patient for the presence of GCC, they found the disease-free patients' lymph nodes showed no signs of the marker. Conversely, GCC was present in every patient whose cancer had returned.

"The earlier trial was on a small scale, and until you do this largertrial, you really can't be sure if testing for GCC is as good as it appears," said Waldman.

The trial, for which recruitment has already begun, is looking at approximately at the Kimmel Cancer Center and the Fox Chase Cancer Center in Philadelphia, the University of Florida in Gainesville, McGill University in Montreal and Conemaugh Memorial Medical Center in Johnstown, PA.

Other Sources: Thomas Jefferson