Patients with diverticulosis have lower incidence of polyps, says new study

Henry Ford Health SystemOct 27 2009

A Henry Ford Hospital study questions the need for aggressive screening for colonic polyps in patients with diverticulosis.

The study sought to determine if asymptomatic patients with diverticular disease are at higher or lower risk for developing colonic polyps, abnormal growths found in the wall of the colon that sometimes become cancerous.

"We found that patients with diverticulosis have a lower incidence of polyps overall and a tendency for less-advanced polyps," says Ali Nawras, M.D., chief of Endoscopy Services, Division of Gastroenterology at Henry Ford Hospital, and lead author of the study. "These results suggest that for patients with diverticulosis, a less-aggressive surveillance regimen could be appropriate."

The study results will be presented Oct. 26 at the American College of Gastroenterology's Annual Scientific Meeting in San Diego.

Colonic polyps and diverticulosis are common conditions in Western countries and both diseases share common predisposing factors such as older age and low-fiber diet. However, there has been conflicting data on the association between the presence of diverticulosis and colonic polyps.

According to the National Digestive Diseases Information Clearing House, about 10 percent of Americans older than 40, and half of those over age 60, have diverticulosis, a condition where small pouches in the lining of the colon bulge outward through weak spots. When the pouches become inflamed, the condition can lead to bleeding, serious infections, small tears or blockages in the colon.

Henry Ford physicians looked at 1,668 patients, all who had undergone full colonoscopy and had an average risk for colon cancer. The case group (899 patients) included those with diverticulosis and the control group (769 patients) did not. The incidence of polyps was significantly lower in the case group, (223, 24%) compared to the control group (336, 43%).

A subanalysis for different polyp sizes and pathologies was also conducted. Polyps were considered high-risk if they were greater than 1 cm in size, or had tubulo-villous or cancer pathology. Subjects with diverticulosis had a significantly lower rate of high-risk polyps, (36, 4.1%), than those without diverticulosis, (76, 6.8%).