New trial launches to identify ways to prevent recurrence of colorectal cancer

Being the third most common non-skin cancer and the third leading cause of cancer-related mortality in men and women in the United States, colorectal cancer can be a devastating disease. Nonetheless, according to the latest statistics from NCI covering the period 2006 to 2010, death rates continue to decline, due in part to improved treatments, and in part to colorectal cancer screening options that are proven to reduce mortality and that have gained acceptance by the public.

Colorectal cancer can still be a deadly disease, and people who have been diagnosed and treated for it are at increased risk for developing a new colon cancer. To address concerns of colorectal cancer recurring after initial treatment, NCI, in collaboration with SWOG, one of the five cooperative groups that together will comprise NCI's National Clinical Trials Network, and Cancer Prevention Pharmaceuticals, Inc., recently announced a phase III trial. The Preventing Adenomas of the Colon with Eflornithine & Sulinidac (PACES) trial looks at whether someone who has been treated for colon cancer in the past can lower his or her risk of having a second primary colorectal cancer or an adenoma (a type of polyp on the colon wall that may be precancerous) by regularly taking one or both of the study drugs, eflornithine and sulindac.  Both drugs work to lower the body's levels of polyamines, a group of naturally-formed molecules that play a role in the development of colorectal cancer. Each drug works in a different manner: eflornithine slows the body's production of polyamines; sulindac helps cells get rid of excess polyamines.

“PACES is an important study that, in addition to studying ways to prevent the recurrence of previously treated colon cancer, will use new genomic technology to help identify those patients with the greatest risk of recurrence,” said Worta McCaskill-Stevens, M.D., chief of the Community Oncology and Prevention Trials Research Group in NCI’s Division of Cancer Prevention.

Researchers chose these two drugs because of an earlier study that looked at their preventive effects in patients who already had at least one adenoma removed from their colon. In that study, participants who took the drug combination lowered their risk of developing another adenoma over the next three years to less than one third of what it was for those who did not take the drugs. And they lowered their chances of developing high-risk adenomas or multiple adenomas during that time by 90 percent. According to McCaskill-Stevens, “this trial will help determine who will most likely benefit from the drugs eflornithine and sulindac.”

SWOG (formerly the Southwest Oncology Group) conducts clinical trials to prevent and treat cancer in adults and is primarily funded by research grants from NCI. It is one of the largest cancer clinical trials cooperative groups in the United States.