Prevalence of Positive Family History of Colorectal Cancer in the Iranian General Population

Individuals with a positive family history of colorectal cancer have an increased risk of developing this type of cancer. The number of affected relatives and the age at diagnosis are two factors that increase the risk of colorectal cancer. The aim of this study was to assess the prevalence of a positive family history of colorectal cancer in a random sample among the Iranian general population. Five thousand five hundred (5500) subjects'' aged≥20 years were randomly selected by cluster sampling and invited to participate in an interview about the occurrence of colorectal cancer in their first- or second-degree relatives. Of all the responders, 162 (2.9%) subjects reported a positive family history of colorectal cancer; 71 (1.24%) reported having one first-degree relative with colorectal cancer diagnosed before the age of 50; or reported two or more first-degree relatives with colorectal cancer. In addition, 83 (1.51%) and 14 (0.25%) subjects reported having one and two or more second-degree relatives with colorectal cancer respectively. The prevalence of a positive family history of colorectal cancer in Iran is lower than the United States and European countries. Identifying high-risk population for colorectal cancer and encouraging them to participate in surveillance protocols is the first step in targeting preventive measures.