Cancer
that begins in the colon is called colon cancer, and
cancer that begins in the rectum is called rectal
cancer. Cancers
affecting either of these
organs may also be called colorectal cancer.
The major type of colorectal cancer is carcinoma.
Lymphoma carcinoid, melanoma, fibrosarcoma and other
types of sarcoma are rare. The exact causes of colorectal
cancer are not known. However, studies show that above
50 age, high-fat, low-fiber diet, polyps and ulcerative
colitis increase a person's chances of developing
colorectal cancer.
The
orthodox treatment of colorectal cancer now mainly
depends on surgery.
Radiation is also used to relieve symptoms. Combination
of radiation and chemotherapy is applied to those
cases with local metastasis, but the effect is not
sure.
Understanding the Cancer Process
Cancer
affects our cells, the body's basic unit of life.
To understand cancer, it is helpful to know what happens
when normal cells become cancerous. The body is made
up of many types of cells. Normally, cells grow, divide,
and produce more cells as they are needed to keep
the body healthy and functioning properly. Sometimes,
however, the process goes astray--cells keep dividing
when new cells are not needed. The mass of extra cells
forms a growth or tumor. Tumors can be either benign
or malignant.
Benign
tumors are not cancer. They often can be removed and,
in most cases, they do not come back. Cells in benign
tumors do not spread to other parts of the body. Most
important, benign tumors are rarely a threat to life.
Malignant tumors are cancer. Cells in malignant tumors
are abnormal and divide without control or order.
These cancer cells can invade and destroy the tissue
around them. Cancer cells can also break away from
a malignant tumor. They may enter the bloodstream
or lymphatic system (the tissues and organs that produce
and store cells that fight infection and disease).
This process, called metastasis, is how cancer spreads
from the original (primary) tumor to form new (secondary)
tumors in other parts of the body.
The
Colon and Rectum
The
colon and rectum are parts of the body's digestive
system, which removes nutrients from food and stores
waste until it passes out of the body. Together, the
colon and rectum form a long, muscular tube called
the large intestine (also called the large bowel).
The colon is the first 6 feet of the large intestine,
and the rectum is the last 8 to 10 inches.
¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡
Colorectal
Cancer
Cancer
that begins in the colon is called colon cancer, and
cancer that begins in the rectum is called rectal
cancer. Cancers affecting either of these organs may
also be called colorectal cancer.
Risk
Factors
The
exact causes of colorectal cancer are not known. However,
studies show that the following risk factors increase
a person's chances of developing colorectal cancer:
Age. Colorectal cancer is more likely to occur as
people get older.
This disease is more common in people over the age
of 50. However, colorectal cancer can occur at younger
ages, even, in rare cases, in the teens.
¡¤ Diet. Colorectal cancer seems to be
associated with diets that are high in fat and calories
and low in fiber. Researchers are exploring how these
and other dietary factors play a role in the development
of 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 increase a person's risk of developing colorectal
cancer.
A rare, inherited condition, called familial polyposis,
causes hundreds of polyps to form in the colon and
rectum. Unless this condition is treated, familial
polyposis is almost certain to lead to colorectal
cancer.
¡¤ Personal medical history. Research
shows that women with a history of cancer of the ovary,
uterus, or breast have a somewhat increased chance
of developing colorectal cancer. Also, a person who
has already had colorectal cancer may develop this
disease a second time.
¡¤ Family medical history. First-degree
relatives (parents, siblings, children) of a person
who has had colorectal cancer are somewhat more likely
to develop this type of cancer themselves, especially
if the relative had the cancer at a young age. If
many family members have had colorectal cancer, the
chances increase even more.
¡¤ Ulcerative colitis. Ulcerative colitis
is a condition in which the lining of the colon becomes
inflamed. Having this condition increases a person's
chance of developing colorectal cancer.
Having one or more of these risk factors does not
guarantee that a person will develop colorectal cancer.
It just increases the chances.
Detecting
Cancer Early
People
who have any of the risk factors described under "Colorectal
Cancer:
Who's at Risk?" 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 listed below. These tests
are used to detect polyps, cancer, or other abnormalities,
even when a person does not have symptoms. Your health
care provider can explain more about each test.
A
fecal occult blood test (FOBT) is a test used to check
for hidden blood in the stool. Sometimes cancers or
polyps can bleed, and FOBT is used to detect small
amounts of bleeding.
A
sigmoidoscopy is an examination of the rectum and
lower colon (sigmoid colon) using a lighted instrument
called a sigmoidoscope.
A
colonoscopy is an examination of the rectum and entire
colon using a lighted instrument called a colonoscope.
A
double contrast barium enema (DCBE) is a series of
x-rays of the colon and rectum. The patient is given
an enema with a solution that contains barium, which
outlines the colon and rectum on the x-rays.
A
digital rectal exam (DRE) is an exam in which the
doctor inserts a lubricated, gloved finger into the
rectum to feel for abnormal areas.
Recognizing
Symptoms
Common
signs and symptoms of colorectal cancer include:
A
change in bowel habits
Diarrhea, constipation, or feeling that the bowel
does not empty completely
Blood
(either bright red or very dark) in the stool
Stools
that are narrower than usual
General
abdominal discomfort (frequent gas pains, bloating,
fullness, and/or cramps)
Weight
loss with no known reason
Constant
tiredness
Vomiting
These symptoms may be caused by colorectal cancer
or by other conditions.
It is important to check with a doctor.
Diagnosing
Colorectal Cancer
To help find the cause of symptoms, the doctor evaluates
a person's medical history. The doctor also performs
a physical exam and may order one or more diagnostic
tests.
X-rays
of the large intestine, such as the DCBE, can reveal
polyps or other changes.
A
sigmoidoscopy lets the doctor see inside the rectum
and the lower colon and remove polyps or other abnormal
tissue for examination under a microscope.
A colonoscopy lets the doctor see inside the rectum
and the entire colon and remove polyps or other abnormal
tissue for examination under a microscope.
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.
Staging
If the diagnosis is cancer, the doctor needs to learn
the stage (or extent) of disease. Staging is a careful
attempt to find out whether the cancer has spread
and, if so, to what parts of the body. More tests
may be performed to help determine the stage. Knowing
the stage of the disease helps the doctor plan treatment.
Listed below are descriptions of the various stages
of colorectal cancer.
Stage
0. The cancer is very early. It is found
only in the innermost lining of the colon or rectum.
Stage
I. The cancer involves more of the inner
wall of the colon or rectum.
Stage
II. The cancer has spread outside the colon
or rectum to nearby tissue, but not to the lymph nodes.
(Lymph nodes are small, bean-shaped structures that
are part of the body's immune system.)
Stage
III. The cancer has spread to nearby lymph
nodes, but not to other parts of the body.
Stage
IV. The cancer has spread to other parts
of the body. Colorectal cancer tends to spread to
the liver and/or lungs.
Recurrent.
Recurrent cancer means the cancer has come back after
treatment.
The disease may recur in the colon or rectum or in
another part of the body. TOP
Orthodox Treatment
Treatment depends mainly on the size, location, and
extent of the tumor, and on the patient's general
health. Patients are often treated by a team of specialists,
which may include a gastroenterologist, surgeon, medical
oncologist, and radiation oncologist. Several different
types of treatment are used to treat colorectal cancer.
Sometimes different treatments are combined.
Surgery
to remove the tumor is the most common treatment for
colorectal cancer. Generally, the surgeon removes
the tumor along with part of the healthy colon or
rectum and nearby lymph nodes. In most cases, the
doctor is able to reconnect the healthy portions of
the colon or rectum. When the surgeon cannot reconnect
the healthy portions, a temporary or permanent colostomy
is necessary. Colostomy, a surgical opening (stoma)
through the wall of the abdomen into the colon, provides
a new path for waste material to leave the body. After
a colostomy, the patient wears a special bag to collect
body waste. Some patients need a temporary colostomy
to allow the lower colon or rectum to heal after surgery.
About 15 percent of colorectal cancer patients require
a permanent colostomy.
Chemotherapy
is the use of anticancer drugs to kill cancer cells.
Chemotherapy may be given to destroy any cancerous
cells that may remain in the body after surgery, to
control tumor growth, or to relieve symptoms of the
disease. Chemotherapy is a systemic therapy, meaning
that the drugs enter the bloodstream and travel through
the body. Most anticancer drugs are given by injection
directly into a vein (IV) or by means of a catheter,
a thin tube that is placed into a large vein and remains
there as long as it is needed. Some anticancer drugs
are given in the form of a pill.
Radiation
therapy, also called radiotherapy, involves the use
of high-energy x-rays to kill cancer cells. Radiation
therapy is a local therapy, meaning that it affects
the cancer cells only in the treated area. Most often
it is used in patients whose cancer is in the rectum.
Doctors may use radiation therapy before surgery (to
shrink a tumor so that it is easier to remove) or
after surgery (to destroy any cancer cells that remain
in the treated area). Radiation therapy is also used
to relieve symptoms.
The radiation may come from a machine (external radiation)
or from an implant (a small container of radioactive
material) placed directly into or near the tumor (internal
radiation). Some patients have both kinds of radiation
therapy.
Biological
therapy, also called immunotherapy, uses the body's
immune system to fight cancer. The immune system finds
cancer cells in the body and works to destroy them.
Biological therapies are used to repair, stimulate,
or enhance the immune system's natural anticancer
function. Biological therapy may be given after surgery,
either alone or in combination with chemotherapy or
radiation treatment. Most biological treatments are
given by injection into a vein (IV).
Clinical
trials (research studies) to evaluate new ways to
treat cancer are an appropriate option for many patients
with colorectal cancer. In some studies, all patients
receive the new treatment. In others, doctors compare
different therapies by giving the promising new treatment
to one group of patients and the usual (standard)
therapy to another group. Research has led to many
advances in the treatment of colorectal cancer.
Through research, doctors explore new ways to treat
cancer that may be more effective than the standard
therapy.
Side Effects of Treatment
The side effects of cancer treatment depend on the
type of treatment and may be different for each person.
Most often the side effects are temporary. Doctors
and nurses can explain the possible side effects of
treatment. Patients should report severe side effects
to their doctor. Doctors can suggest ways to help
relieve symptoms that may occur during and after treatment.
Surgery
causes short-term pain and tenderness in the area
of the operation. Surgery for colorectal cancer may
also cause temporary constipation or diarrhea. Patients
who have a colostomy may have irritation of the skin
around the stoma. The doctor, nurse, or enterostomal
therapist can teach the patient how to clean the area
and prevent irritation and infection.
Chemotherapy
affects normal as well as cancer cells. Side effects
depend largely on the specific drugs and the dose
(amount of drug given). Common side effects of chemotherapy
include nausea and vomiting, hair loss, mouth sores,
diarrhea, and fatigue. Less often, serious side effects
may occur, such as infection or bleeding.
Radiation
therapy, like chemotherapy, affects normal as well
as cancer cells. Side effects of radiation therapy
depend mainly on the treatment dose and the part of
the body that is treated. Common side effects of radiation
therapy are fatigue, skin changes at the site where
the treatment is given, loss of appetite, nausea,
and diarrhea. Sometimes, radiation therapy can cause
bleeding through the rectum (bloody stools).
Biological
therapy may cause side effects that vary with the
specific type of treatment. Often, treatments cause
flu-like symptoms, such as chills, fever, weakness,
and nausea.