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Boosting Colon Cancer Survival

By Jeffrey Norris, UCSF Science Cafe | March 29, 2007

Colon cancer is largely preventable and curable when detected early through routine screening. But patients who skip screening or who fall prey to particularly aggressive colon cancers may already have widespread disease by the time they are diagnosed.

Colon cancer that has spread to other organs, called metastatic colon cancer, historically has almost always been fatal. For this reason, colon cancer remains the second leading cause of US cancer death, after lung cancer.

But now new drugs, often combined with older chemotherapies, in some cases are shrinking widespread cancers to a degree that makes surgery an option and complete elimination of these cancers a possibility. Among metastatic colon cancers, those in which metastasis beyond the colon shrinks to a single, surgically removable mass in the liver often have the best prognosis.

Two of the newest targeted treatments approved for colon cancer are being combined with standard chemotherapy in a new, nationwide clinical trial. While chemotherapies tend to target all rapidly dividing cells, the new treatments -- called biologics -- more specifically target biochemical pathways that are abnormal in cancer cells.

UCSF Oncologist Leads National Study
UCSF chief of gastrointestinal oncology Alan Venook leads the new clinical trial, called CALGB 80405. The trial is sponsored by the National Cancer Institute through its Clinical Trials Cooperative Groups Program. A consortium of oncologists at academic medical centers, as well as community oncologists, will enroll 2,278 patients in the study.

The new treatment combinations will be evaluated to determine whether any of the combinations improve survival of patients with metastatic colon cancer beyond the current average of 22 months. Researchers will measure cures, overall average survival time and how long cancers are prevented from spreading again.

"Here's a study of advanced colon cancer in which we're wondering what percentage of patients we can cure, whereas 10 years ago, we would not have expected to cure any of these patients," Venook says. "It's an area of great excitement."

Novel chemotherapy combinations first boosted survival in cases of widespread colon cancer to about one in 10, Venook says. And still more recent clinical trials suggest that the addition of one biologic drug to chemotherapy may double survival to two in 10 patients.

Read more at Jeffrey Norris, UCSF Science Cafe