Polyposis Syndromes

Abstract

Colorectal cancer (CRC) is the third most common type of cancer and the second leading cause of cancer death in men and women. Although about one third of cancers arise in patients with a family history of CRC, only 5% arise in the setting of mendelian-inherited disorders. Patients without a family history but with a significant polyp burden (> 20 polyps) should be considered to have polyposis syndrome. The field of polyposis syndromes continues to advance, based on new genetic discoveries that define the genetic etiologies of polyposis syndromes. When considered in relation to an individual’s phenotype, these discoveries help guide screening and treatment based on the cancer risk created by specific mutations. Patients with polyposis syndromes carry an increased risk of CRC and some other extracolonic cancers. Future research will provide additional insight into the cause of polyposis syndromes without a currently detectable gene defect and will improve early identification and cancer prevention in affected individuals. Identification of additional molecular characteristics may lead to a more personalized approach to treatment for these individuals. This review contains 7 figures, 11 tables and 52 references. Key words: attenuated familial polyposis, colorectal cancer risk, familial adenomatous polyposis, hamartomatous polyposis syndrome, juvenile polyposis syndrome, MUTYH-associated polyposis, Peutz-Jeghers syndrome, polyposis syndromes, screening guidelines, serrated polyposis syndrome