Colorecatal Cancer Screening
Colorectal (large bowel) cancer is a disease in which
malignant (cancer) cells form in the inner lining of the
colon or rectum. Together, the colon and rectum make up
the large bowel or large intestine. The large intestine
is the last segment of the digestive system (the
esophagus, stomach, and small intestine are the first
three sections). The large bowel's main job is to
reabsorb water from the contents of the intestine so
that solid waste can be expelled into the toilet. The
first several feet of the large intestine is the colon
and the last 6 inches is the rectum.
Most colon
and rectal cancers originate from benign wart-like
growths on the inner lining of the colon or rectum
called polyps. Not all polyps have the potential to
transform into cancer. Those that do have the potential
are called adenomas. It takes more than 10 years in most
cases for an adenoma to develop into cancer. This is why
some colon cancer prevention tests are effective even if
done at 10-year intervals. This 10-year interval is too
long, in some cases, such as in persons with ulcerative
colitis or Crohn's colitis, and in persons with a strong
family history of colorectal cancer or adenomas.
Commonality -
Colorectal cancer is the second most common cancer
killer overall and third most common cause of
cancer-related death in the United States in both males
and females. Lung and prostate cancers are more common
in men and lung and breast in women. In 2007, there will
be 153,000 new cases and 52,000 deaths from colorectal
cancer.
Screening for
Colorectal Cancer - Screening means looking for
cancer or polyps when patients have no symptoms. Finding
colorectal cancer before symptoms develop dramatically
improves the chance of survival.
Identifying and
removing polyps before they become cancerous actually
prevents the development of colorectal cancer.
At Risk
*
Everyone age 50 and older. - The average age to develop
colorectal cancer is 70 years, and 93% of cases occur in
persons 50 years of age or older. Current
recommendations are to begin screening at age 50 if
there are no risk factors other than age for colorectal
cancers. A person whose only risk factor is their age is
said to be at average risk.
* Men and women - Men
tend to get colorectal cancer at an earlier age than
women, but women live longer so they 'catch up' with men
and thus the total number of cases in men and women is
equal.
* Anyone with a family history of colorectal
cancer. - If a person has a history of two or more
first-degree relatives (parent, sibling, or child) with
colorectal cancer, or any first-degree relatives
diagnosed under age 60, the overall colorectal cancer
risk is three to six times higher than that of the
general population. For those with one first-degree
relative diagnosed with colorectal cancer at age 60 or
older, there is an approximate two times greater risk of
colon cancer than that observed in the general
population. Special screening programs are used for
those with a family history of colorectal cancer. A
well-documented family history of adenomas is also an
important risk factor.
* Anyone with a personal
history of colorectal cancer or adenomas at any age, or
cancer of endometrium (uterus) or ovary diagnosed before
age 50. - Persons who have had colorectal cancer or
adenomas removed are at increased risk of developing
additional adenomas or cancers. Women diagnosed with
uterine or ovarian cancer before age 50 are at increased
risk of colorectal cancer. These groups should be
checked by colonoscopy at regular intervals, usually
every 3 to 5 years. Woman with a personal history of
breast cancer have only a very slight increase in risk
of colorectal cancer.
Symptoms of Colorectal Cancer - Symptoms of
colorectal cancer vary depending on the location of the
cancer within the colon or rectum, though there may be
no symptoms at all. The prognosis tends to be worse in
symptomatic as compared to asymptomatic individuals. The
most common presenting symptom of colorectal cancer is
rectal bleeding. Cancers arising from the left side of
the colon generally cause bleeding, or in their late
stages may cause constipation, abdominal pain, and
obstructive symptoms. On the other hand, right-sided
colon lesions may produce vague abdominal aching, but
are unlikely to present with obstruction or altered
bowel habit. Other symptoms such as weakness, weight
loss, or anemia resulting from chronic blood loss may
accompany cancer of the right side of the colon. You
should promptly see your doctor when you experience any
of these symptoms.
Why
You Should Get Checked - Adenomas can grow for
years and transform into cancer without producing any
symptoms. By the time symptoms develop, it is often too
late to cure the cancer, because it may have spread.
Screening identifies cancers earlier and actually
results in cancer prevention when it leads to removal of
adenomas (pre-cancerous polyps).