Early-onset colorectal cancer risk extends to second- and third-degree relatives

Introduction: Family history is a risk factor for colorectal cancer (CRC), however whether family history also contributes to non-syndromic early-onset CRC is unknown. Methods: We estimated risk to first-, second-, and third-degree relatives of early-onset CRC cases in the Utah Pedigree Database. Results: We observed elevated risks beyond RR = 2.0 for early-onset CRC among first- and second-degree relatives of early-onset CRC cases, with RRs of 6.0 and 3.1, respectively. Discussion: Relatives of early-onset CRC cases are at higher risk of both early-onset CRC and CRC at any age, and the location is not necessarily similar to the affected relative.