New Tool Developed to Predict Colorectal Cancer Risk
A new online tool for calculating colorectal cancer risk in men and women age 50 or
older was launched today, based on a new risk-assessment model developed by researchers at
the National Cancer Institute, part of the National Institutes of Health. This new tool
may assist health care providers and their patients in making informed choices about when
and how to screen for colorectal cancer and can be used in designing colorectal cancer
screening and prevention trials. An article describing the new risk-assessment model and a
second article describing its validation appear online December 29, 2008, in the Journal
of Clinical Oncology. The risk assessment tool is available on the NCI Web site at
and people using this tool should work with their
health care providers to interpret the results.
Using easily obtainable information (e.g. personal and family medical history,
lifestyle behaviors, and age), the tool provides an estimate of an individual's risk of
developing colorectal cancer over certain time periods (within five years, 10 years and
over the course of a lifetime). This risk-assessment model is the first to provide an
absolute risk estimate for colorectal cancer (i.e. the probability of developing
colorectal cancer over a given period of time) for the general, non-Hispanic white
population age 50 or older in the United States.
"Much like the NCI's breast cancer and melanoma risk assessment tools, this new
colorectal cancer risk assessment tool should prove useful not only in counseling patients
on their individual risk, but also in helping plan type and frequency of screening
intervention studies," said NCI Director John E. Niederhuber, M.D. "As we move toward an
era of personalized medicine, the ability to assess an individual patient's cancer risk
and thereby improve our ability to apply appropriate prevention measures is of vital
Approximately one in 18 Americans will develop colorectal cancer at some point during
his or her lifetime. In 2008, an estimated 148,810 people will be diagnosed with
colorectal cancer in the United States and another 49,960 will die of the disease. There
are several screening options for colorectal cancer, including fecal occult blood tests
(which look for the presence of blood in stool samples), sigmoidoscopy (which uses a
lighted probe to inspect the sigmoid, or lowest part, of the colon), colonoscopy (which
uses a lighted probe to inspect the entire colon), and computerized tomographic
colonography, also known as virtual colonoscopy (which uses CT scans, a type of x-ray, to
create images of the entire colon). Having additional information about an individual's
risk could aid health care providers and their patients in making decisions about which
screening regimen to pursue.
To develop the risk-assessment model, researchers used data from two large
population-based case-control studies. Several factors that have been previously
associated with colorectal cancer risk were shown to be predictive of a colorectal cancer
diagnosis in those two studies, including age; family history of colorectal cancer;
consumption of vegetables; body mass index; cigarette smoking; use of aspirin or other
non-steroidal anti-inflammatory drugs; physical activity; use of hormone replacement
therapy; previous history of sigmoidoscopy and/or colonoscopy; and history of polyps.
Estimates of relative risk (comparisons of risk in one group to another) from the
case-control studies were combined with population-based data on colorectal cancer
incidence from NCI's SEER (Surveillance, Epidemiology and End Results) cancer registries
to make the model broadly applicable in the United States.
"This colorectal cancer risk model should provide physicians and their patients a new
tool to help make informed decisions about cancer screening and other cancer prevention
strategies. It may also assist policy makers in evaluating the usefulness of current and
future population colorectal cancer screening approaches," said Andrew Freedman Ph.D.,
lead author of the paper which describes the development of the risk-assessment model.
To test the accuracy of the risk-assessment model, the researchers compared expected
numbers of colorectal cancer cases predicted by the model to the observed numbers of cases
identified in the NIH-AARP Diet and Health Study, a large study that follows AARP members
and collects information about nutrition and health. From information about individual
risk factors that was collected when participants entered the study, the researchers used
the new model to estimate the number of men and women who would be expected to develop
colorectal cancer. According to Ruth Pfeiffer, Ph.D., who was the senior author of the
validation study, "The colorectal cancer risk-assessment tool predicted the numbers of
colorectal cancer diagnoses well overall, and in most risk categories."
Because the majority of participants in the two case-control studies used to develop
the model were non-Hispanic whites age 50 or older, the researchers were unable to
estimate relative risks for other age and racial/ethnic groups. However, there are plans
to expand the tool to include these populations in the future. In addition, the tool is
not applicable to individuals with certain gastrointestinal disorders (such as ulcerative
colitis or Crohn's disease), certain inherited genetic conditions (such as familial
adenomatous polyposis or hereditary nonpolyposis colorectal cancer) or a personal history
of colorectal cancer. These conditions are known to carry a very high risk of developing
In addition to the standard Web tool, a mobile Web-based version for use on
Internet-enabled mobile devices and the source code for the model will soon be made
available to researchers. It is important that users of the online tool work with their
primary health care provider to interpret the results and plan a course of action
regarding colorectal cancer screening.
NCI leads the National Cancer Program and the NIH effort to dramatically reduce the
burden of cancer and improve the lives of cancer patients and their families, through
research into prevention and cancer biology, the development of new interventions, and the
training and mentoring of new researchers. For more information about cancer, please visit
the NCI Web site at http://www.cancer.gov or call NCI's Cancer Information Service at
Freedman AN, Slattery ML, Ballard-Barbash R, Willis G, Cann BJ, Pee D, Gail MH, and
Pfeiffer RM. A Colorectal Cancer Risk Prediction Tool for White Men and Women Without
Known Susceptibility. JCO. Online December 29, 2008.
Park Y, Freedman AN, Gail MH, Pee D, Hollenbeck A, Schatzkin A, and Pfeiffer RM.
Validation of a Colorectal Cancer Risk Prediction Model among Whites 50 Years Old and
Over. JCO. Online December 29, 2008.
To view the new Colorectal Cancer Risk Tool online, please visit http://www.cancer.gov/colorectalcancerrisk .
For more information on understanding cancer risk, please visit http://understandingrisk.cancer.gov .