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.