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Colorectal Cancer Detection and Prevention
What Is Colorectal Cancer?
The colon and rectum are parts of the body’s digestive
system, which removes fluids, mostly water, from what we eat and stores
waste until it passes out of the body. Together, the colon and rectum form a long, muscular tube
called the large intestine. The colon is the first four feet of the large
intestine, and the rectum is the last eight to ten inches. Cancer of the
colon and rectum are referred to as colorectal cancer (CRC).
Colorectal cancer is the second leading cause of cancer death in the United
States. However, if detected early, colorectal cancer can be cured. With
simple preventive steps, you can greatly reduce your risk of developing
this disease. It is important for you to understand your risks for colorectal
cancer, the warning signs, and screening tests that can detect precancerous
and cancerous growths.
Colorectal cancer develops from benign tumors called polyps. A polyp is
a grape-like growth on the inside wall of the colon or rectum that may
turn into cancer. Polyps grow slowly over many (three to fifteen) years.
Most people do not develop polyps until after the age of 50. Approximately
one in 20 polyps can become cancerous if not removed. To prevent colorectal
cancer, it is important to get screened to find out if you have polyps,
and to have them removed if present. Removing polyps has been shown to
prevent cancer.
What Are the Risk Factors?
The exact causes of colorectal cancer are not known.
However, studies show that the following risk factors increase a person’s
chances for developing colorectal cancer:
- Age. As people get older they are more likely to develop colorectal
cancer. Approximately 90% of colorectal cancers occur in people over
the age of 50. However, colorectal cancer can occur at younger ages and,
in rare cases, in the teens.
- Diet. Diets high in fat and low in fiber seem to be associated
with colorectal cancer.
- Polyps. Polyps are benign growths on the
inner wall of the colon and rectum. They are fairly common in people
over age 50. Some types of polyps, called adenomas, increase a person’s risk of developing
colorectal cancer.
- Personal medical history. Research shows women with a history
of ovarian and uterine cancers have an increased risk of developing colorectal
cancer.>
- Family medical history. First-degree relatives (parents, siblings,
children) of a person who has had colorectal cancer have an increased
risk for colorectal cancer. The risk increases as the number of family
members diagnosed with colorectal cancer before age 60 increases.
- Ulcerative colitis and Crohn’s colitis (Inflammatory
Bowel Disease). People who suffer from longstanding ulcerative colitis or Crohn’s colitis, chronic
inflammatory disorders of the colon, have an increased risk for colorectal cancer.
Having one or more of these risk factors does not guarantee
that a person will develop colorectal cancer. It merely increases the chances.
You may want to talk to your doctor about these risk factors.
Lifestyle Changes To Lower Your
Risk of Colorectal Cancer
Screening is the single most important thing you can
do to lower your risk of colorectal cancer.
Early detection is the best way to improve the chance of
successful treatment and reduce the number of deaths caused by colorectal
cancer. The ONLY proven way to prevent colon cancer is to identify
and systematically remove polyps. When you combine screening with an overall
healthy lifestyle, you benefit even more. More than half of all colorectal
cancers could be prevented if everyone followed these healthy lifestyle
tips:
- Be physically active
- Maintain a healthy body weight
- Eat less red meat
- Take a multivitamin with folate daily
- Limit the amount of alcohol you drink
- Eat fruits and vegetables
- Don’t smoke.
When Should You Be Screened for
Colorectal Cancer?
Screening for colorectal cancer should
be a part of routine care for all adults starting at age 50. In those
people with first-degree
relatives with colorectal cancer, screening should start at an earlier
age. Groups that have a higher incidence of colorectal cancer — those with
hereditary conditions, such as familial polyposis, hereditary nonpolyposis
colon cancer and inflammatory bowel disease — should consult with their
health care providers as to the appropriate time to begin screening. .
More common conditions with an increased risk include:
- A personal history of colorectal cancer or adenomas
- A first-degree family history of colorectal cancer or adenomas
- A personal history of ovarian or endometrial cancer.
Screening Tests for Colorectal Cancer
Screening tests for colon cancer are extremely important
for detecting and removing pre-cancerous polyps. Screening can also detect
colorectal cancer at an early stage and, therefore, increase the cure rate.
Unfortunately, only a minority of adults over 50 years old have regular
screening tests that could detect a cancer early enough for curative treatment.
People who have any of the aforementioned risk factors should ask a doctor
when to begin checking for colorectal cancer, what tests to have, and how
often to have them. The doctor may suggest one or more of the tests below.
These tests are used to detect polyps, or colon cancer, even when a person
does not have symptoms. Your health care provider can explain more about
each test and help you decide what test is best for you.
The screening tests range from less effective but less invasive
to more invasive but highly effective tests. The screening tests are listed below:
- 1. A fecal occult blood test (FOBT) is a test used to check
for hidden blood in the stool. Cancers or
polyps can bleed intermittently and can be detected by FOBT. This
test is recommended annually for persons beginning at age 50 who are
at average risk.
- 2. A flexible sigmoidoscopy is
an examination of the lower 1/4 to 1/3 of the colon lining
using a flexible, lighted instrument called a sigmoidoscope. No sedative
is given. This test is recommended
every five years beginning at age 50 for people at average risk.
- The combination of a flexible sigmoidoscopy every
five years and FOBT yearly is often used in clinical practice
to screen for CRC beginning at age 50 for people at average risk.
- A double contrast barium enema (DCBE)
is an x-ray of the colon and rectum. A tube is inserted into the rectum,
and a dye called contrast along with air fills the colon. This test
is recommended every five years beginning at age 50 for people at average
risk.
- A colonoscopy is performed by a
specialist, who will use a long, flexible, lighted
tube called the colonoscope to view the entire colon and rectum for
polyps or cancer. The test is performed
after administration of a mild sedative. It is considered the gold
standard exam because it provides a direct view of the entire colon
and rectum and allows for the detection and removal of polyps. If a
screening colonoscopic exam shows no sign of polyps, the next examination
is recommended in 10 years.
What Are the Warning Signs?
** No symptoms<>
Once a cancer has developed, common signs and symptoms include:
- Rectal bleeding
- A change in bowel habits, especially in the shape of the stool (e.g., narrow like a pencil)
- Diarrhea, constipation, or feeling that the rectum does not empty completely
- Blood (either bright red or very dark) in the stool
- General abdominal discomfort (frequent gas pains, bloating, fullness, and/or cramps)
- Weight loss with no known reason
- Constant fatigue.
These symptoms may be caused by colorectal
cancer or by other less serious conditions. It is important to consult
your health care provider regarding any symptoms you may be experiencing.
** It is important to note that many
people may not experience any symptoms related to CRC, therefore, regular
screening exams after age 50 are encouraged.
Diagnosing Colorectal
Cancer
To identify the cause of symptoms, the doctor
will review your history. The doctor also performs a physical exam and
may order one or more of the following diagnostic tests:
- A sigmoidoscopy lets the clinician
see inside the rectum and the lower colon and sample polyps or other
abnormalities.
- A colonoscopy lets the doctor examine
the entire colon and remove polyps or sample abnormal areas.
- A polypectomy is the removal of
a polyp during a sigmoidoscopy or colonoscopy.
- A biopsy is the removal of a tissue
sample for examination under a microscope by a pathologist to make
a diagnosis.
- A barium enema can be performed
to evaluate patients with lower intestinal symptoms but is felt not
to be as effective as colonoscopy. If an abnormality is from the barium
enema, a colonoscopy is performed to obtain a biopsy or remove a polyp.
- CT scans of the abdomen and pelvis can reveal possible growths
How Is Colorectal Cancer Treated?
Treatment depends mainly
on the size, location, and extent of the tumor and on the patient’s
general health. A team of specialists, which may include a gastroenterologist,
surgeon, medical oncologist, and radiation oncologist, often treats patients. Several
different types of treatment are used to treat colorectal cancer. Sometimes
different treatments are combined:
- Surgery
- Chemotherapy
- Radiation therapy
- Combination of surgery, chemotherapy and/or radiation therapy
- Clinical trials of new therapies.
The Importance of Follow-up Care
Follow-up care after treatment
for patients with colon polyps or colon cancer is important. Regular
checkups ensure that changes in health are noticed. If the cancer returns
or a new cancer develops, it can be identified and treated as soon as
possible. Checkups may include a physical exam, colonoscopy, chest x-rays,
CT scans, and lab tests. Between scheduled checkups, a person who has
had colorectal cancer should report any health problems to the doctor
as soon as they appear.
Glossary
Adenoma: Specific type
of polyp with the potential to become cancerous
Benign: Non-cancerous.
Chemotherapy: The
use of drugs to kill cancer cells.
Clinical trials: Research
studies used to evaluate new ways to treat cancer.
Malignant: Cancerous;
cells in malignant tumors are abnormal and divide without control or
order and can spread to other organs.
Polyps: Tissue growths
that protrude from the inner lining of the colon or rectum.
Radiation therapy: Also
called radiotherapy, involves the use of high energy x-rays to
kill cancer cells.
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