Models to predict the risk of patients developing colorectal cancer are powerful tools that can be used to help augment screening and prevention strategies. A group of researchers from Fred Hutchinson Cancer Research Center in Seattle combined a large collection of data into one model that has the power to predict colorectal cancer risk in patients.
Writing in the journal Gastroenterology, the researchers published their findings in the article, “A Model to Determine Colorectal Cancer Risk Using Common Genetic Susceptibility Loci.” Data from over 12,000 individuals spanning 21 years and six separate studies in the United States and Germany were used to generate the model. Risks were determined using sex, age, family history of colorectal cancer, genetic risk score, and history of endoscopic examinations. Genetic risk scores were assigned based on the number of genes an individual carried that were previously identified as common colorectal cancer susceptibility loci.
“We identified a colorectal cancer genetic risk score that independently predicted which patients in the training set would develop colorectal cancer,” stated the researchers. By including this genetic risk score, the researchers’ model that used sex, age, family history, and endoscopic examinations was improved significantly.
Although age was not as large of a factor in determining an individual’s colorectal cancer risk, the model was able to predict the age at which patients became more susceptible to develop colorectal cancer. In men who were already at a high risk for the disease, the starting age for risk was 42 years, and in men who were at a low risk for colorectal cancer, the starting age for risk was 52 years. These ages give a suggested time for when men may want to start colorectal cancer screening. For example, if a man had a family history of colorectal cancer and a genetic risk score of 90% or higher, he would be at a high risk and may wish to start screening at 42 years of age. These patterns were similar for women, as well.
A negatively correlating factor was history of endoscopy. Patients who had undergone an endoscopy were less likely to be diagnosed with colorectal cancer, especially cancers of the distal colon and rectum. The heightened awareness of colon health gained by undergoing an endoscopy may have helped individuals proactively prevent colorectal cancer, suggesting a benefit to adhering to age recommendations for screening.