Who is at risk for colorectal cancer?
Every one of us is at risk for colorectal cancer. The
lifetime risk is 1 in 18 people or about 6% of American men and women. Most
people who develop colorectal cancer have no particular risk factors.
Although the exact cause for the development of precancerous
colon polyps that lead to colorectal cancer is not known, there are some factors
that increase a person’s risk of developing colorectal polyps and cancer. These
risk factors include:
Age
The risk of developing colorectal polyps and cancer
increases as we age. Precancerous polyps are common in people over 50 and can
affect 40% of people over the age of 60. Colorectal cancer that develops from
precancerous polyps is usually seen in people over the age of 60 however it can
develop in younger people.
Gender
Women and men are at equal risk for the development
of colorectal polyps and cancer.
Lifestyle factors
You may be at increased risk for
developing colorectal cancer if you drink alcohol, smoke, don’t get enough
exercise, and if you are overweight.
Smoking
Smoking increases the risk of precancerous polyps
and colorectal cancer by two- to three-fold.
Obesity
Obesity has been linked to an increased risk of
precancerous colon polyps and colon cancer. The risk is increased up to 2 times
compared to individuals who have a normal body mass index.
Diet
A diet high in fat and calories and low in fiber,
fruits and vegetables has been linked to a greater risk of developing colorectal
cancer.
- Polyps. There are a variety of polyps that can form on the
inner wall of the colon or rectum. Precancerous polyps that can turn into
colorectal cancer include adenomatous polyps. Adenomas are precancerous
polyps that are considered precursors, or the first step toward colon and
rectal cancer. Another pathway to cancer has recently been discovered and
found to arise from large hyperplastic polyps or sessile serrated polyps
(also known as sessile serrated adenomas). Individuals with numerous polyps,
including adenomas, hyperplastic polyps, or other types of polyps such as
hamartomas or juvenile polyps are often affected with a genetic
predisposition to polyposis and colorectal cancer and are a special group of
individuals who should be managed differently than people with only 1 to 2
colorectal polyps.
- Inflammatory bowel disease. Ulcerative colitis and Crohn’s colitis
are conditions in which the lining of the colon becomes inflamed. People
with these conditions, when present for more than seven years and affecting
a large portion of the colon are at greater risk for developing colorectal
cancer.
- Personal history. Research shows that some women who have a history
of ovarian or uterine cancer, especially at a young age have a somewhat
increased risk of developing colorectal cancer. Also, a person who already
has had colorectal adenomas or cancer may develop the disease a second time.
Family history
Parents, siblings, and children of a person
who has had colorectal adenomas or cancer are at least 2-3 times more likely to
develop colorectal cancer themselves. Sometimes colon cancer clusters in
families. In these cases, more cancers are occurring than would be expected by
chance, yet they do not appear to be clearly hereditary. Very little is known
about the causes of cancer in these families. It is possible that interactions
are occurring between genes and the environment or among several genes. This
type of moderately increased cancer risk can be called a "familial colon
cancer."
About 5% to 10% of colon cancers are believed to be
hereditary. Hereditary susceptibility to cancer can be inherited and can be
passed on within a family. When a person has a hereditary cancer susceptibility,
he or she has inherited a copy of a cancer susceptibility gene with a mutation.
Individuals who inherit a mutation in a cancer susceptibility gene have a much
greater chance for developing cancer. However, not everyone with a cancer
susceptibility gene mutation will develop cancer.
The most common inherited colorectal cancer syndromes are
hereditary nonpolyposis colorectal cancer (HNPCC), familial adenomatous
polyposis (FAP), and MYH-associated polyposis (MAP). Other syndromes
include juvenile polyposis syndrome (JPS), Peutz-Jeghers syndrome (PJS), and the
PTEN-hamartoma tumor syndrome. Genetic testing is available for all of these
syndromes.
Having one or more of these risk factors does not guarantee that
you will develop colorectal cancer. However, you should talk about these risk
factors with your doctor. He or she may be able to suggest ways to reduce your
chances of developing colorectal cancer.
© Copyright 1995-2009 The Cleveland Clinic Foundation. All rights reserved.
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This information is provided by the Cleveland Clinic and is not intended to replace the medical advice of your doctor or health care provider. Please consult your health care provider for advice about a specific medical condition. This document was last reviewed on: 7/21/2009…#11922
