Cancer risk increased in relatives of patients with serrated polyposis

Serrated polyposis is one of the most common polyp syndromes in clinical practice and is often unrecognized during colonoscopy.

Many patients with serrated polyposis do not have a family history of colorectal cancer, and we have not yet discovered any genes responsible for the condition. Nevertheless, results of RCTs suggest that serrated polyposis has an inherited basis at least in some kindreds.

A common recommendation is to begin surveillance colonoscopy in first-degree relatives of patients with serrated polyposis at age 40, or at 10 years below the age at which any colorectal cancer diagnosis occurred in the family and to perform colonoscopy every 5 years — or more often if indicated by polyp findings.

According to the World Health Organization, criteria for the diagnosis of serrated polyposis (formerly called hyperplastic polyposis syndrome) include the presence of >20 serrated polyps (either sessile serrated polyps or hyperplastic polyps) throughout the colon; 5 serrated polyps proximal to the sigmoid (of which 2 are >10mm in size); or any serrated polyp proximal to the sigmoid in a first-degree relative of a patient with serrated polyposis.

To estimate the risk for colorectal and other cancers in relatives of patients with serrated polyposis, investigators evaluated a cohort of 1639 first- and second-degree relatives of 100 index patients with serrated polyposis. Fifty-four colorectal cancers were observed in first-degree relatives (standardized incidence ratio, 5.16; P<0.001) and 48 in second-degree relatives (SIR, 1.38; P=0.04). First-degree relatives had a higher risk for pancreatic cancer (SIR, 3.64; P=0.003) but not for cancers of the stomach, brain, breast, or prostate. The cumulative risk for colorectal cancer at age 70 in first-degree relatives was 15% in men and 12% in women. If the index case was diagnosed at <50 years, the cumulative risk increased to 24% in men and 19% in women.

The authors concluded, ”Our finding that relatives of serrated polyposis patients are at significantly increased risk of colorectal and pancreatic cancer adds to the accumulating evidence that serrated polyposis has an inherited component.”

 

Citation(s):

Win AK et al. Cancer risks for relatives of patients with serrated polyposis. Am J Gastroenterol 2012 May; 107: 770.

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