What is Colorectal
Cancer?
Colorectal cancer is a type of cancer caused by the
growth of malignant cells in the colon or rectum. The
colon and the rectum are part of the large intestine,
which is part of the digestive system. Colorectal cancer
is believed to develop from non-cancerous growths, called
polyps, on the walls of the colon or rectum. Over time,
polyps may begin to grow abnormally and become cancerous.
If undiagnosed and untreated, colorectal cancer can
spread to other parts of the body.
According to the American Cancer Society and the American
Gastroenterological Association:
- Colorectal cancer is the third most common cancer
diagnosed in men and in women in the United States
- Colorectal cancer is the second-leading cause of
cancer-related deaths in the United States, claiming
more than 56,000 lives annually
- 80 to 90 million Americans-some 25 percent of all
American adults-face an increased risk of developing
colorectal cancer because of age, heredity and lifestyle
factors
- Increased screening, earlier detection, and treatment
advances have contributed to the nationwide decline
in death rates from colorectal cancer over the last
15 years
- Today, 1 million American women and men have survived
colorectal cancer
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Risk Factors
A risk factor is anything that may increase your chance
of developing a disease. Different diseases, including
cancer, have different risk factors. Although these
factors may put you at greater risk, they do not necessarily
cause the disease. Some people with one or more risk
factors never develop colorectal cancer, while others
develop the disease without having any of the following
risk factors:
- Age-More than 90 percent of adults diagnosed with
colorectal cancer are over age 50
- Diet-Some studies suggest a link between colorectal
cancer and a diet high in fat (particularly animal
fats) and calories, but low in fiber
- Physical inactivity-A sedentary lifestyle increases
your risk of developing different diseases, including
colorectal cancer
Obesity-If you are severely overweight, you're at
increased risk of dying of colorectal cancer
Diabetes-Diabetes increases your risk of developing
colorectal cancer by approximately 30 to 40 percent
Smoking-Recent studies indicate that smokers are 30
to 40 percent more likely than nonsmokers to die from
colorectal cancer. Smoking may be responsible for
causing about 12% of fatal colorectal cancers, according
to the American Cancer Society
- Polyps-Benign growths on the wall of the colon
or rectum are common in adults over age 50, and are
believed to lead to colorectal cancer. Polyps can
be removed during a screening colonoscopy
- Personal and family history-People who have had
colorectal cancer, as well as ovarian, uterine, or
breast cancers, have a slightly increased risk for
colorectal cancer. Also, if your parents or siblings
have had colorectal cancer, you face an increased
risk of developing it yourself
- Digestive diseases-People with disorders that cause
long-term inflammation of the colon wall (such as
ulcerative colitis and Crohn's disease) are more susceptible
to colorectal cancer
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Common Symptoms
IIn the earliest stages of colorectal cancer, you won't
feel anything or know you have it. But, as the disease
progresses, subtle symptoms may begin to emerge. See
your doctor if you experience any of these warning signs:
- Rectal bleeding or blood in the stool
- Recurrent stomach pain or cramping
- Unusual changes in bowel habits, such as narrow,
ribbon-like stools
- Discomfort during bowel movements or constantly
feeling like you need to have a bowel movement
- Loss of appetite, unexplained weight loss
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Screening and Diagnosis
For all types of cancer, routine screening and early
detection are essential to successful treatment and
recovery. To find the cause of symptoms, a physical
examination and medical testing are required. During
the exam, your doctor will review your personal medical
history, family history, and potential symptoms. You
will also receive one or more of the following medical
tests:
- Digital rectal examination (DRE) -By inserting
a gloved, lubricated finger into the rectum, doctors
can feel for lumps or unusual masses in the rectum
- Fecal occult blood test-A test kit you complete
in the privacy of your own home and return to your
doctor's office for evaluation of hidden blood in
the stool
- Sigmoidoscopy-An outpatient procedure using a long,
flexible, lighted tube to check the rectum and lower
part of the colon for polyps and cancerous tumors
- Colonoscopy-An outpatient procedure using a colonoscope,
which is a long, flexible, lighted tube (much longer
than a sigmoidoscope), that allows your doctor to
view the entire colon and rectum
- Barium enema (lower GI series)-A liquid containing
barium is put into the rectum and a series of x-rays
are taken of the lower gastrointestinal tract
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Stages of Colorectal
Cancer
Once a diagnosis is made, doctors conduct additional
tests to stage the cancer, or determine if the cancer
has spread and how far. Staging helps your doctor develop
an appropriate treatment plan.
As colorectal cancer advances from Stage 0 to Stage
IV, tumors grow through the lining of the rectum or
colon and spread to lymph nodes and other organs.
- Stage 0 (carcinoma
in situ): Cancer is found in the innermost
lining of the rectum or colon only
- Stage I: Cancer
has spread beyond the innermost wall of the rectum
or colon to the middle layers
- Stage II: Cancer
is found in the middle layers or outside of the colon
or rectum, but not in the lymph nodes
- Stage III: Cancer
has invaded nearby lymph nodes, but not other parts
of the body
- Stage IV: Other
parts of the body, such as the lungs or liver, are
affected by the cancer
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Common Treatment Options
Treatment for colorectal cancer is based on the type,
stage, and size of the tumor, as well as your personal
preferences, prognosis, and ability to tolerate certain
medical procedures or medications. The goal of treatment
is to preserve healthy tissue while destroying tumors
at their point of origin, as well as any cancer cells
that have spread throughout the body.
Surgery
Surgery is the most common type of treatment for colorectal
cancer. Doctors often use colonoscopy to remove small
tumors and cancerous polyps in the colon or upper rectum.
For larger tumors, surgical oncologists remove cancerous
cells and some of the nearby healthy tissue through
an opening in the abdomen. Adjacent lymph nodes also
may be removed.
Chemotherapy
Chemotherapy is a type of treatment that uses drugs
to stop the growth of cancer cells, either by killing
the cells or by stopping the cells from dividing. Depending
on the type and stage of the cancer, chemotherapy may
be given as the primary treatment or as an adjuvant
(additional) treatment to surgery. Chemotherapy drugs
can be taken orally or by injection depending on the
type and stage of the cancer and the type of drug protocol
your doctor has prescribed. It is important to discuss
your treatment protocol with your treatment team so
you are aware of any possible side effects.
Radiation
therapy
Radiation therapy is often used when colon cancer has
attached to an internal organ or the lining of the abdomen
and the surgeon cannot be certain that all the cancer
has been removed. For rectal cancer, radiation therapy
is usually given to prevent the cancer from coming back
in the pelvis where the tumor started.
Radiation therapy is a non-surgical method of treatment
of cancer and other diseases using penetrating beams
of high-energy waves called x-rays or gamma rays. Radiation
injures or destroys tumor cells by damaging their genetic
material, making it impossible for these cells to continue
to grow. There are two types of radiation therapy:
- External-beam radiation therapy - Specialized medical
equipment is used to deliver radiation to the tumor
site from outside the body.
- Internal radiation therapy - Radioactive material
is placed in the body near the cancer cells (also
called implant radiation or brachytherapy)
The way the radiation therapy is given depends on the
type and stage of the cancer being treated.
