ABSTRACT
An estimated 1% to 10% of all colorectal tumors (CRC) are related to high-penetrance genes. Families with Lynch Syndrome, caused by mutations in MMR repair genes, present a high frequency, not only of CRC, but also extracolonic tumors. Objective:To verify the frequency of CRC and extracolonic cancers in families that meet Amsterdam I and II criteria. Methods: Families had been included that meet Amsterdam I and II criteria, in the Registry of Colorectal Cancer of A. C. Camargo Hospital from 1992 to 2007. Family history was taken and stored in the Cyrillic® 2.1 software. Data collection forms were filled. Results:1578 individuals were identified, and 337 of them presented tumors. CRC was the most frequent, with 221 individuals,with a mean age of 46 years at diagnosis. The most frequent extracolonic tumors were breast (17 cases), endometrium (15), stomach (14), urinary (12), leukemia (9), and prostate (6). Discussion: As expected, the age at diagnosis of colorectalcancer was younger than the general population; breast tumor was the most frequent; molecular studies must differentiate patients with Lynch Syndrome (LS) from those with familial colorectal cancer.