Stomach cancer
(also called gastric cancer) is a commoncancer of
the digestive tract. More than 95% of stomach cancers
are adenocarcinomas.
The other five percent of stomach cancers are either
squamous cells cancers, lymphomas, sarcomas or neuroendocrine
tumours.
As with many cancers, the conventional treatment options
for stomach cancer are surgery, chemotherapy and radiotherapy.
These treatments can remove or in some degree, inhibit
the cancer and relieve the symptoms, but it also brings
side effects that are always beyond what you would
have thought.
Introduction
Each
year, about 24,000 people in the United States learn
that they have cancer of the stomach. This booklet
will give you important information about the symptoms,
diagnosis, and treatment of stomach cancer. It also
has information to help you deal with this disease
if it affects you or someone you know.
The Stomach
The
stomach is part of the digestive system. It is located
in the upper
abdomen, under the ribs. The upper part of the stomach
connects to the esophagus, and the lower part leads
into the small intestine.
When
food enters the stomach, muscles in the stomach wall
create a
rippling motion that mixes and mashes the food. At
the same time, juices made by glands in the lining
of the stomach help digest the food. After about 3
hours, the food becomes a liquid and moves into the
small intestine, where digestion continues.
What
Is Cancer?
Cancer
is a group of more than 100 different diseases. They
affect the body's basic unit, the cell. Cancer occurs
when cells become abnormal and divide without control
or order.
Like
all other organs of the body, the stomach is made
up of many types of cells. Normally, cells divide
to produce more cells only when the body needs them.
This orderly process helps keep us healthy.
If
cells keep dividing when new cells are not needed,
a mass of tissue
forms. This mass of extra tissue, called a growth
or tumor, can be benign or malignant.
Benign
tumors are not cancer. They can usually be removed
and, in most cases, they do not come back. Most important,
cells from benign tumors do not spread to other parts
of the body. Benign tumors are rarely a threat to
life.
Malignant tumors are cancer. Cancer cells can invade
and damage tissues and organs near the tumor. Also,
cancer cells can break away from a malignant tumor
and enter the bloodstream or lymphatic system. This
is how cancer spreads from the original (primary)
tumor to form new tumors in other parts of the body.
The spread of cancer is called metastasis.
Stomach
cancer (also called gastric cancer) can develop in
any part of the stomach and may spread throughout
the stomach and to other organs. It may grow along
the stomach wall into the esophagus or small intestine.
It
also may extend through the stomach wall and spread
to nearby lymph nodes and to organs such as the liver,
pancreas, and colon. Stomach cancer also may spread
to distant organs, such as the lungs, the lymph nodes
above the collarbone, and the ovaries.
When
cancer spreads to another part of the body, the new
tumor has the same kind of abnormal cells and the
same name as the primary tumor. For example, if stomach
cancer spreads to the liver, the cancer cells in the
liver are stomach cancer cells. The disease is metastatic
stomach cancer (it is not liver cancer). However,
when stomach cancer spreads to an ovary, the tumor
in the ovary is called a Krukenberg tumor. (This tumor,
named for a doctor, is not a different disease; it
is metastatic stomach cancer. The cancer cells in
a Krukenberg tumor are stomach cancer cells, the same
as the cancer cells in the primary tumor.)
Causes
of Stomach Cancer
The
stomach cancer rate in the United States and the number
of deaths from this disease have gone down dramatically
over the past 60 years. Still, stomach cancer is a
serious disease, and scientists all over the world
are trying to learn more about what causes this disease
and how to prevent it.
At this time, doctors cannot explain why one person
gets stomach cancer and another does not. They do
know, however, that stomach cancer is not contagious;
no one can "catch" cancer from another person.
Researchers
have learned that some people are more likely than
others to develop stomach cancer. The disease is found
most often in people over age 55. It affects men twice
as often as women, and is more common in black people
than in white people. Also, stomach cancer is more
common in some parts of the world--such as Japan,
Korea, parts of Eastern Europe, and Latin America--than
in the United States. People in these areas eat many
foods that are preserved by drying, smoking, salting,
or pickling. Scientists believe that eating foods
preserved in these ways may play a role in the development
of stomach cancer. On the other hand, fresh foods
(especially fresh fruits and vegetables and properly
frozen or refrigerated fresh foods) may protect against
this disease.
Stomach
ulcers do not appear to increase a person's risk (chance)
of
getting stomach cancer. However, some studies suggest
that a type of bacteria, Helicobacter pylori, which
may cause stomach inflammation and ulcers, may be
an important risk factor for this disease. Also, research
shows that people who have had stomach surgery or
have pernicious anemia, achlorhydria, or gastric atrophy
(which generally result in lower than normal amounts
of digestive juices) have an increased risk of stomach
cancer.
Exposure
to certain dusts and fumes in the workplace has been
linked to a higher than average risk of stomach cancer.
Also, some scientists believe smoking may increase
stomach cancer risk.
Recognizing
Symptoms
Stomach
cancer can be hard to find early. Often there are
no symptoms in the early stages and, in many cases,
the cancer has spread before it is found. When symptoms
do occur, they are often so vague that the person
ignores them.
Stomach cancer can cause the following:
Indigestion
or a burning sensation (heartburn);
Discomfort or pain in the abdomen;
Nausea and vomiting;
Diarrhea or constipation;
Bloating of the stomach after meals;
Loss of appetite;
Weakness and fatigue; and
Bleeding (vomiting blood or having blood in the stool).
Any of these symptoms may be caused by cancer or by
other, less serious health problems, such as a stomach
virus or an ulcer. Only a doctor can tell the cause.
People who have any of these symptoms should see their
doctor. They may be referred to a gastroenterologist,
a doctor who specializes in diagnosing and treating
digestive problems. These doctors are sometimes called
gastrointestinal (or GI) specialists.
Diagnosing
To find the cause of symptoms, the doctor asks about
the patient's
medical history, does a physical exam, and may order
laboratory studies. The patient may also have one
or all of the following exams:
Fecal
occult blood test--a check for hidden (occult) blood
in the stool.
This test is done by placing a small amount of stool
on a plastic slide or on special paper. It may be
tested in the doctor's office or sent to a laboratory.
This test is done because stomach cancer sometimes
causes bleeding that cannot be seen. However, noncancerous
conditions also may cause bleeding, so having blood
in the stool does not necessarily mean that a person
has cancer.
Upper
GI series --x-rays of the esophagus and stomach
(the upper gastrointestinal, or GI, tract. The x-rays
are taken after the patient drinks a barium solution,
a thick, chalky liquid. (This test is sometimes
called a barium swallow.) The barium outlines the
stomach on the x-rays, helping the doctor find tumors
or other abnormal areas. During the
test, the doctor may pump air into the stomach to
make small tumors easier to see.
Endoscopy
--an exam of the esophagus and stomach using
a thin, lighted tube called a gastroscope, which is
passed through the mouth and esophagus to the stomach.
The patient's throat is sprayed with a local anesthetic
to reduce discomfort and gagging. Patients also may
receive medicine to relax them. Through the gastroscope,
the doctor can look directly at the inside of the
stomach. If an abnormal area is found, the doctor
can remove some tissue through the gastroscope. Another
doctor, a pathologist, examines the tissue under a
microscope to check for cancer cells.
This procedure --removing tissue and examining
it under a microscope--is called
a biopsy. A biopsy is the only sure way to know whether
cancer cells are present.
Staging
If
the pathologist finds cancer cells in the tissue sample,
the patient's doctor needs to know the stage, or extent,
of the disease. Staging exams and tests help the doctor
find out whether the cancer has spread and, if so,
what parts of the body are affected. Because stomach
cancer can spread to the liver, the pancreas, and
other organs near the stomach as well as to the lungs,
the doctor may order a CT (or CAT) scan, an ultrasound
exam, or other tests to check these areas.
Staging
may not be complete until after surgery. The surgeon
removes nearby lymph nodes and may take samples of
tissue from other areas in the abdomen. All of these
samples are examined by a pathologist to check for
cancer cells. Decisions about treatment after surgery
depend on these findings.
Orthodox
Treatment
Cancer of the stomach is difficult to cure unless
it is found in an early stage (before it has begun
to spread). Unfortunately, because early stomach cancer
causes few symptoms, the disease is usually advanced
when the diagnosis is made. However, advanced stomach
cancer can be treated and the symptoms can be relieved.
Treatment for stomach cancer may include surgery,
chemotherapy, and/or radiation therapy. New treatment
approaches such as biological therapy and improved
ways of using current methods are being studied in
clinical trials. A patient may have one form of treatment
or a combination of treatments.
Surgery
is the most common treatment for stomach cancer. The
operation is called gastrectomy. The surgeon removes
part (subtotal or partial gastrectomy) or all (total
gastrectomy) of the stomach, as well as some of the
tissue around the stomach. After a subtotal gastrectomy,
the doctor connects the remaining part of the stomach
to the esophagus or the small intestine. After a total
gastrectomy, the doctor connects the esophagus directly
to the small intestine. Because cancer can spread
through the lymphatic system, lymph nodes near the
tumor are often removed during surgery so that the
pathologist can check them for cancer cells. If cancer
cells are in the lymph nodes, the disease may have
spread to other parts of the body.
Chemotherapy
is the use of drugs to kill cancer cells. This type
of treatment is called systemic therapy because the
drugs enter the bloodstream and travel through the
body.
Clinical
trials are in progress to find the best ways to use
chemotherapy to treat stomach cancer. Scientists are
exploring the benefits of giving chemotherapy before
surgery to shrink the tumor, or as adjuvant therapy
after surgery to destroy remaining cancer cells. Combination
treatment with chemotherapy and radiation therapy
is also under study. Doctors are testing a treatment
in which anticancer drugs are put directly into the
abdomen (intraperitoneal chemotherapy). Chemotherapy
also is being studied as a treatment for cancer that
has spread, and as a way to relieve symptoms of the
disease.
Most
anticancer drugs are given by injection; some are
taken by mouth. The doctor may use one drug or a combination
of drugs. Chemotherapy is given in cycles: a treatment
period followed by a recovery period, then another
treatment, and so on. Usually a person receives chemotherapy
as an outpatient (at the hospital, at the doctor's
office, or at home). However, depending on which drugs
are given and the patient's general health, a short
hospital stay may be needed.
Radiation
therapy (also called radiotherapy) is the use of high-energy
rays to damage cancer cells and stop them from growing.
Like surgery, it is local therapy; the radiation can
affect cancer cells only in the treated area. Radiation
therapy is sometimes given after surgery to destroy
cancer cells that may remain in the area. Researchers
are conducting clinical trials to find out whether
it is helpful to give radiation therapy during surgery
(intraoperative radiation therapy). Radiation therapy
may also be used to relieve pain or blockage
Side
Effects of Orthodox Treatment
It
is hard to limit the effects of therapy so that only
cancer cells are removed or destroyed. Because healthy
cells and tissues also may be damaged, treatment can
cause unpleasant side effects.
The
side effects of cancer treatment are different for
each person, and they may even be different from one
treatment to the next. Doctors try to plan treatment
in ways that keep side effects to a minimum; they
can help with any problems that occur. For this reason,
it is very important to let the doctor know about
any problems during or after treatment.
Surgery
Gastrectomy is major surgery. For a period of time
after the surgery, the person's activities are limited
to allow healing to take place. For the first few
days after surgery, the patient is fed intravenously
(through a vein). Within several days, most patients
are ready for liquids, followed by soft, then solid,
foods. Those who have had their entire stomach removed
cannot absorb vitamin B12, which is necessary for
healthy blood and nerves, so they need regular injections
of this vitamin. Patients may have temporary or permanent
difficulty digesting certain foods, and they may need
to change their diet. Some gastrectomy patients will
need to follow a special diet for a few weeks or months,
while others will need to do so permanently. The doctor
or a dietitian (a nutrition specialist) will explain
any necessary dietary changes.
Some
gastrectomy patients have cramps, nausea, diarrhea,
and dizziness shortly after eating because food and
liquid enter the small intestine too quickly. This
group of symptoms is called the dumping syndrome.
Foods containing high amounts of sugar often make
the symptoms worse. The dumping syndrome can be treated
by changing the patient's diet. Doctors often advise
patients to eat several small meals throughout the
day, to avoid foods that contain sugar, and to eat
foods high in protein. To reduce the amount of fluid
that enters the small intestine, patients are usually
encouraged not to drink at mealtimes. Medicine also
can help control the dumping syndrome. The symptoms
usually disappear in 3 to 12 months, but they may
be permanent.
Following
gastrectomy, bile in the small intestine may back
up into the
remaining part of the stomach or into the esophagus,
causing the symptoms of an upset stomach. The patient's
doctor may prescribe medicine or suggest over-the-counter
products to control such symptoms.
Chemotherapy
The side effects of chemotherapy depend mainly on
the drugs the patient receives. As with any other
type of treatment, side effects also vary from person
to person. In general, anticancer drugs affect cells
that divide rapidly. These include blood cells, which
fight infection, help the blood to clot, or carry
oxygen to all parts of the body. When blood cells
are affected by anticancer drugs, patients are more
likely to get infections, may bruise or bleed easily,
and may have less energy. Cells in hair roots and
cells that line the digestive tract also divide rapidly.
As a result of chemotherapy, patients may have side
effects such as loss of appetite, nausea, vomiting,
hair loss, or mouth sores. For some patients, the
doctor may prescribe medicine to help with side effects,
especially with nausea and vomiting. These effects
usually go away gradually during the recovery period
between treatments or after the treatments stop.
Radiation Therapy
Patients who receive radiation to the abdomen may
have nausea, vomiting, and diarrhea. The doctor can
prescribe medicine or suggest dietary changes to relieve
these problems. The skin in the treated area may become
red, dry, tender, and itchy. Patients should avoid
wearing clothes that rub; loose-fitting cotton clothes
are usually best. It is important for patients to
take good care of their skin during treatment, but
they should not use lotions or creams without the
doctor's advice.
Patients
are likely to become very tired during radiation therapy,
especially in the later weeks of treatment. Resting
is important, but doctors usually advise patients
to try to stay as active as they can.
Biological Therapy
The side effects of biological therapy vary with the
type of treatment.
Some cause flu-like symptoms, such as chills, fever,
weakness, nausea, vomiting, and diarrhea. Patients
sometimes get a rash, and they may bruise or bleed
easily. These problems may be severe, and patients
may need to stay in the hospital during treatment.