New Tool Developed to Predict Colorectal
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
(NCI), 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 www.cancer.gov/colorectalcancerrisk,
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 the type and frequency of screening interventions," 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 importance."
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 that 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 colorectal cancer.
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.
To view the new Colorectal Cancer Risk Tool online, please visit:
For more information about understanding cancer risk, please visit:
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 1-800-4-CANCER (1-800-422-6237).
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Medical Research Agency — includes 27 Institutes and Centers
and is a component of the U.S. Department of Health and Human Services.
It is the primary federal agency for conducting and supporting basic,
clinical and translational medical research, and it investigates
the causes, treatments, and cures for both common and rare diseases.
For more information about NIH and its programs, visit www.nih.gov.
Reference: 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.