Validated Colorectal Cancer Risk Assessment Tool Available Online

Validated Colorectal Cancer Risk Assessment Tool Available Online

NCI researchers have developed one of the first colorectal cancer (CRC) absolute risk assessment models for people aged 50 to 85 without known genetic susceptibility to the disease, using data from two large case-control studies and validating the model in the NIH-AARP Diet and Health Study population. The tool uses answers about lifestyle, screening, and family history of CRC to calculate a person’s 5-year, 10-year, and lifetime risk of developing the disease. Both the development and validation papers were published December 29 in the Journal of Clinical Oncology, and an online risk assessment tool based on the model is now available for use by physicians at http://www.cancer.gov/ColorectalCancerRisk/.

“This colorectal cancer risk model provides physicians and their patients with a new tool to help make informed decisions about colorectal cancer screening and other prevention strategies. It may also assist policy makers in evaluating the usefulness of current and future population colorectal cancer prevention approaches,” said Dr. Andrew Freedman, lead author of the study, in an accompanying press release.

Dr. Freedman of NCI’s Division of Cancer Control and Population Sciences and Dr. Ruth Pfeiffer of NCI’s Division of Cancer Epidemiology and Genetics (DCEG) led the team that developed the model using data from two population-based, case-control studies, one for colon cancer and one for rectal cancer, and cancer incidence rates from the SEER database. Since non-Hispanic white men and women aged 50 years or older made up the majority of participants in both case-control studies, the researchers restricted their model to this group.

They determined the relative risks for a cancer diagnosis in three different areas of the colon and rectum based on known risk factors, including history of CRC screening, body mass index, and family history of CRC. The researchers also constructed a short risk-assessment patient questionnaire that easily captures the information used in the model.

To assess the model’s performance, the researchers, led by DCEG’s Dr. Yikyung Park, used the model to estimate the number of CRC cases expected in the 155,345 men and 108,057 women in the NIH-AARP cohort. They then compared those results to the actual number of cases diagnosed in that cohort between 1995 and 2003. They found that their model was well calibrated, with the estimated-to-observed ratio for CRC diagnoses being 0.99 in men and 1.05 in women.

The researchers are in the process of updating the Web tool with data from SEER to improve accuracy for other racial and ethnic groups.

Colonoscopy Reduces Death from Cancer in the Left Colon, but Not the Right

In a large case-control study performed by researchers at the University of Toronto, patients who had undergone colonoscopy at least once were significantly less likely to die of colorectal cancer (CRC) arising in the left side of the colon (the part of the colon closest to the rectum) than patients who had never had a colonoscopy. However, colonoscopy did not reduce mortality from CRC in the right side of the colon, according to results published in the December 15 Annals of Internal Medicine.

Using four Ontario-based databases, the investigators matched 10,292