Epidemiology of hereditary colorectal cancer.

Hereditary colorectal cancers comprise less than 5 % of all colorectal cancers and are defined as heritable conditions characterized by an apparently increased risk of colorectal cancer in individuals (mutant carriers in the germline), compared with the risk in the general population. Among the various known hereditary colorectal cancers, Lynch syndrome is the most common, followed by familial adenomatous polyposis. Other rarer diseases have been described, such as MUTYH-associated polyposis, polymerase proofreading-associated polyposis, hamartomatous polyposis syndromes (Peutz-Jeghers syndrome, juvenile polyposis syndrome, and PTEN hamartomatous syndrome). The early-onset of colorectal cancer and the development of other malignant neoplasms in various organs are characteristics that are common to these diseases. We herein document the epidemiologic characteristics of these rare diseases.