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 were 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