Better test for colon cancer spread

February 29, 2008 3:34:31 PM PST

The nation's colon cancer experts met today at Jefferson University's Kimmel Cancer Center to exchange information on the latest advances in therapy and imaging.

One major step forward discussed today is a new test being developed to determine how far colon cancer has spread.

Dr. Scott Waldman, a clinical pharmacologist and one of the developers, says the test looks for a protein called GCC that is a marker for colon cancer. GCC is also a marker for traveler's diarrhea, and in fact, helps determine its severity.

If GCC shows up in lymph nodes at the cancer site, doctors know whether chemotherapy is needed or not.

Dr. Waldman says, "If you have disease that's confined to the intestine, typically you don't need treatment with chemotherapy."

For years, doctors have used slice biopsies of those nodes to determine whether cancer has spread, and if so, how much. However, by taking individual slices of the nodes, it is possible to miss clusters of cancerous cells. In addition, the test depends on the visual acuity of pathologists, who examine the cells under microscropes.

Dr. Waldman says this new test is much more sensitive than what's used now. He notes, "While a pathologist's eye can detect 1 cancer cell in 200 normal cells, this test can detect as little as 1 cancer cell in 1 to 10 million normal cells."

A Canadian company has commercial rights to the test, and hopes to have it on the market by late this year.