Familial segregation in the occurrence and severity of periampullary neoplasms in familial adenomatous polyposis.

Background: Familial adenomatous polyposis (FAP) patients often develop periampullary adenomas that may progress to periampullary cancer, a common cause of death in this population. The risk of periampullary cancer in FAP is unclear, and variables that predict the occurrence and severity of periampullary tumors are not well understood. The specific aim of this study was to determine whether the risk of periampullary neoplasia segregates in specific FAP families.

Materials And Methods: A total of 144 FAP patients from 74 families were either screened by gastroduodenoscopy (n = 132) or information was obtained from surgical or autopsy reports (n = 12). The severity of periampullary neoplasia was recorded for each patient and graded based on maximum polyp size and histology. Linear regression was used to determine the significance of a number of variables with respect to periampullary neoplasia. A blood sample was available from at least one member of 50 unrelated families and used to detect germline mutations in codons 686 through 1693 of the adenomatous polyposis coli (APC) gene.

Results: Statistically significant familial segregation was found for the incidence and severity of periampullary neoplasia (P < 0.02). Age was also a statistically significant variable (P < 0.01). No correlation was observed between specific APC germline mutations and periampullary polyp frequency and severity.

Conclusions: The occurrence and severity of periampullary neoplasms in patients with FAP segregates in families. This familial association may be related to as yet unidentified modifier genes or perhaps common environmental factors. These results should prove useful in developing upper gastrointestinal screening protocols for FAP patients at risk for periampullary neoplasia.