Just as you inherited
your parent’s physical features, you may have inherited their susceptibility
for colorectal
cancer.
If this type of cancer
runs in your family, you've probably heard your parents or other relatives talk
about it. You may have learned that family members — either your immediate
family (first degree) or your aunts, uncles and cousins (second degree) — have
had polyps. Or, you know that certain cancers, such as breast, ovarian and
uterine, seem to run in your family.
The fact that certain
family members have had some form of cancer means that you may have inherited
that risk as well. If possible, find out who in your family was affected, and
how. Sharing that medical history with your doctor may go a long way in helping
to prevent cancer, determine your screening frequency for it, and decide on the
best possible treatment if you do get the disease.
Colorectal cancer
specialists have identified high-risk populations to help families decide when
screening is needed. Primary characteristics include:
- Patients with one first-degree
relative who was diagnosed with colorectal cancer or advanced adenoma
(polyps) when younger than age 60
- Patients with two first-degree
relatives diagnosed with colorectal cancer or advanced adenoma at any age
- Patients with one first-degree
relative diagnosed with colorectal cancer or advanced adenoma at age 60 or
older
- Patients with two or more
second-degree relatives who were diagnosed with advanced adenoma
In 20 to 30 percent of
colorectal cancer cases, a cancer gene begins with the patient, so family
history may not be helpful. Some people don't have large families so they don't
have a family history to consult. But in 70 to 80 percent of colorectal cancer
cases, family history is extremely important.
Experts estimate that
between 10 and 15 percent of all familial colorectal cancers developed from an
inherited risk. These are the genetic disorders commonly tested in families
with a history of colorectal or other cancers. Because these are general
descriptions, talk with your doctor about specific characteristics and testing.
Lynch syndrome
One of the most common
disorders that occurs in families is Lynch syndrome. It can cause colon cancer
to occur in people before age 50 and can be passed on to children.
People with Lynch
syndrome — among the most common hereditary cancer syndromes — may need
frequent colonoscopies, as often as every one to two years, starting at age 35.
It's estimated that as many as one in every 300 individuals may be carriers of
an alteration in a gene associated with Lynch syndrome.
Familial adenomatous polyposis
This inherited
disorder is known to run in families and may affect as many as half of the
members. Patients with familial adenomatous polyposis develop hundreds and even
thousands of polyps in the colon. It often is detected in people in their teens
and early 20s.
Peutz-Jeghers syndrome
This disorder is
characterized by noncancerous polyps that can increase the risk of developing
certain types of cancer. People with Peutz-Jeghers syndrome have pigmentation
defects that appear as small, dark-colored spots on the mouth, hands and feet.
Ashkenazi Jewish descent
Jewish people who are
Ashkenazi, or of eastern European decent, have a higher risk for colorectal
cancer than other ethnic groups.
In the past,
colorectal cancer specialists looked primarily at the patient and the patient's
family history as powerful indicators of colorectal cancer risk. Today,
specialists are identifying genes that may increase the risk of the disease in
families.
That research is
making a difference. Researchers are studying whole panels of genes. When they
find a suspicious gene in a patient, the patient's family is tested as well.
If you have the slightest concern that you might have inherited a family gene, get screened.
