Hereditary nonpolyposis colorectal cancer and familial colorectal cancer in Central part of Iran, Isfahan

BACKGROUND: There is a lack of data on familial aggregation of colorectal cancer (CRC) in Iran. We aimed to determine the frequency of hereditary nonpolyposis colorectal cancer (HNPCC) and familial colorectal cancer (FCC) and to determine the frequency of extracolonic cancers in these families in Isfahan. METHODS: We reviewed documents of all patients with a pathologically confirmed diagnosis of CRC admitted to Isfahan referral hospitals between 1995 and 2006. We also studied our CRC registry at Poursina Hakim Research Institute from 2003 to 2008. We found HNPCC and FCC families based on the Amsterdam II criteria and interviewed them for family history of CRC and extracolonic tumors. The family history was taken at least up to the second-degree relatives. RESULTS: During 1996 to 2008, a total of 2580 CRC cases have been diagnosed. We found 14 HNPCC and 53 FCC families. Mean age of CRC at diagnosis was 48.0 +/- 14.6 and 49.0 +/- 13.9 years in the HNPCC and FCC families, respectively (p > 0.05). The total numbers of observed extracolonic tumors were 70 (21.6%; mean age = 53.6 +/- 11.0 years) and 157 (13.8%; mean age = 54.8 +/- 18.0 years) in HNPCC and FCC families, respectively (p > 0.05). CRC was respectively found in 52 and 76 members of the HNPCC and FCC families, revealing the frequency of HNPCC and FCC as 2.0% (52/2580) and 2.9% (76/2580), respectively. CONCLUSIONS: We found a relative high frequency of HNPCC (2.0%) and FCC (2.9%) among CRC cases in our society and high incidence of extracolonic tumors in their families. Further studies focusing on molecular basis in this field and designing a specific screening and national cancer registry program for HNPCC and FCC families should be conducted.