In a new study published in the journal Cancer Prevention Research, researchers have identified a promising prevention treatment for patients with familial adenomatous polyposis (FAP), which lead to colorectal cancer if not treated properly.

The findings reported that the treatment led to a near-complete blockade of cancer growth pathways in polyps isolated from FAP patients. Further, the patients showed evidence of activated immune responses aimed at destroying pre-cancerous polyps. Familial adenomatous polyposis is an inherited disorder.

Patients with FAP develop hundreds to thousands of precancerous growths called polyps in their large and small intestine. Many of the people choose to have surgery to remove their colon, but they may still develop polyps in their small intestine. The prior study identified a two-drug combination of sulindac and erlotinib which significantly reduced precancerous polyps in FAP patients.

The researchers further developed these findings. The team conducted genomic analyses of polyps collected from FAP patients who participated in the trial. The researchers compared gene expression in tissue from patients who received the treatment with those who did not.

The results revealed that the drug combination led to a nearly complete blockage of pathways involved in polyp growth. Additionally, immune pathways in polyps activated in treated FAP patients. The findings suggested that the sulindac-erlotinib treatment activated natural defence responses aimed at polyp eradication.

Deborah Neklason, PhD, an investigator of the study was surprised to see the immune response to the polyps in these patients. According to Neklason, "We thought treating the patients with this combination of drugs would stop the polyps from growing, and stop new polyps from developing. But what we actually saw was polyps shrinking. We saw them start to go away."

Don Delker, PhD, research assistant professor of Internal Medicine at the University of Utah oversaw the genomic analysis performed on the samples. It was encouraging to see such a strong response in the tissues and the blocking of pathways from which cancer develops.

The information would be used to find better treatments for patients with precancerous growths that can develop from the pathways. The results would help to address an unmet clinical need in patients with FAP who develop cancers of the small intestine as very limited treatment options are available to them. The researchers are planning to conduct additional clinical studies in FAP patients to identify optimal dosing of the drug combination.