Familial aspects of colorectal cancers in southern littoral of Caspian Sea.

Abstract

About 50,000 new cancer cases occur annually in Iran, of which gastrointestinal (GI) cancers are the most common. Colorectal cancers (CRC) account for the third and fourth most prevalent cancers amongst Iranian men and women, respectively. Since CRC has some well-known hereditary forms with differences in their prevalence according to regional heterogeneity, we designed a study to assess familial aspects of this cancer in subjects who reside in Mazandaran Province, Iran. We interviewed all CRC patients who attended a private GI clinic during 1999-2007, with histologically confirmed diagnoses of colorectal adenocarcinoma, about their family histories of CRC and age at diagnosis. Pedigrees were drawn up to second-degree relatives. A total of 293 CRC cases enrolled in the study, of which 152 were male and 141 were female. The mean age of patients was 52.6±15.2 years. Of these, 98 patients (33.5%) were under the age of 45. A total of 66 cases (22.5%) had familial histories of CRC, being significantly more prevalent in younger subjects (11.2% vs. 44.9%, P<0.0001). Thirty-two patients (10.9%) fulfilled the criteria for hereditary non-polyposis colon cancer. In addition, right-sided colon cancers were more prevalent in those with positive familial histories (P<0.05). Due to the frequency of early-onset CRC and familial syndromes, a more intense screening protocol for early detection of CRC should be developed for this population.