| STOMACH
CANCER
What Is Stomach Cancer?
Stomach cancer (also called gastric cancer) starts in
the stomach. In everyday speech, the word "stomach"
is often used to refer to the area of the body between
the chest and the pelvic area. For instance, people
with pain in the appendix, small intestine, colon, or
gallbladder might say they have a "stomach ache."
The medical term for this area is the abdomen and doctors
would describe the symptom as "abdominal pain."
The difference is important because the stomach is only
one of many organs in the abdomen that can develop cancer.
So stomach cancer should not be confused with other
cancers that can occur in the abdomen. These other cancers
can cause different symptoms. They are treated differently
and have a different outlook for survival (prognosis).
After food has been chewed and swallowed, it passes
down a tube called the esophagus and empties into the
stomach. The stomach is a sack-like organ that holds
food and mixes it with gastric juice to begin the process
of digestion.
Cancer can start in any part of the stomach. Symptoms,
treatment options, and the outlook for survival can
all vary depending on where the cancer begins.
The stomach itself is made up of 5 layers. It helps
to know about these layers because as cancer grows deeper
into them, the outlook for the patient gets worse. Starting
from the inside and working out, the innermost layer
is called the mucosa. This is where the stomach acid
and digestive juices are made. Next is a supporting
layer called the submucosa. This is surrounded by the
muscularis, a layer of muscle that moves and mixes the
stomach contents. The next 2 layers, the subserosa and
the serosa (the outermost layer) act as wrapping for
the stomach.
Most of the time stomach cancer starts in the mucosa.
Stomach cancer probably grows slowly over many years.
Before a true cancer develops, there are usually changes
that take place in the lining of the stomach. These
early changes rarely produce symptoms and therefore
often are not noticed.
Stomach cancer can spread in several different ways.
It can grow through the wall of the stomach and eventually
grow into nearby organs. It can also spread to the lymph
nodes (bean-sized collections of immune system cells)
and then through the lymph system. If cancer spreads
this way, the outlook for a cure gets worse.
Stomach cancer can spread in different ways. It can
grow through the wall of the stomach and into nearby
organs. It can also spread into the lymph system through
the lymph nodes—small bean-sized structures that
help fight infections. When stomach cancer is more advanced,
it can travel through the bloodstream and form deposits
of cancer cells in organs such as the liver, lungs,
and bones. But even though it has spread to other organs,
it is still called stomach cancer.
Most cancers of the stomach are of a type called adenocarcinomas.
This cancer develops from cells that form the lining
of the innermost layer, the mucosa. The term “stomach
cancer” almost always refers to this type of cancer.
Lymphomas, gastric stromal tumors, and carcinoid tumors
are other, much less common, tumors that are found in
the stomach. The treatment and outlook for these cancers
are different from that of adenocarcinoma and are not
covered here. The ACS has separate information about
these cancers.
How Many People Get Stomach Cancer?
We know that there will be about 22,280 new cases of
stomach cancer in the United States in 2006. About 11,430
people will die of this disease. Two thirds of the people
found to have stomach cancer are older than 65. The
risk of a person getting stomach cancer in their lifetime
is about 1 in 100.
Stomach cancer is much more common in some countries
other than the United States. It was once a leading
cause of cancer deaths in this country but it is now
much less common. The reasons for this decline are not
completely known, but they may be linked to more use
of refrigeration for food storage and less use of salted
and smoked foods. Some doctors think that an important
factor is the use of antibiotics to treat infections
in children. These drugs can kill the bacteria (Helicobacter
pylori) that may be a major cause of this disease.
What Causes Stomach Cancer?
A risk factor is anything that increases a person's
chance of getting a disease such as cancer. Different
cancers have different risk factors. Some risk factors,
such as smoking, can be controlled. Others, like a person's
age or family history, can't be changed. But having
a risk factor, or even several, doesn’t mean that
a person will get the disease.
Scientists have found several risk factors that make
a person more likely to develop stomach cancer. The
major factors are listed below:
Bacteria infection: Many doctors think
that infection with bacteria called Helicobacter pylori
may be a major cause of stomach cancer. Long-term infection
with this germ can lead to inflammation and damage to
the inner layer of the stomach, a possible pre-cancerous
change. This bacterium is also linked to some types
of lymphoma of the stomach. But most people who carry
this germ in their stomachs never develop cancer
Diet: An increased risk of stomach
cancer is linked to diets high in smoked foods, salted
fish and meats, and pickled vegetables. On the other
hand, eating whole grain products and fresh fruits and
vegetables that contain vitamins A and C appears to
lower the risk of stomach cancer.
Tobacco and alcohol abuse: Smoking
just about doubles the risk of stomach cancer for smokers.
While some studies have linked alcohol use to stomach
cancer, this is not certain.
Obesity: Being very overweight (obese)
is a major cause of many cancers, including cancer of
the stomach.
Earlier stomach surgery: Stomach cancer
is more likely to occur in people who have had part
of their stomach removed to treat other problems such
as ulcers.
Pernicious anemia: In this disease,
the stomach doesn’t make enough of a protein that
allows the body to absorb vitamin B12 from foods. This
can lead to anemia (a shortage of red blood cells).
Patients with this disease also have a slightly increased
risk of stomach cancer.
Menetrier disease: This rare disease involves changes
in the stomach lining that in turn are linked to a risk
of stomach cancer.
Gender: Stomach cancer is more than
twice as common in men as it is in women.
Ethnicity: The rate of stomach cancer
is higher in Hispanics and African Americans than in
non-Hispanic whites. The highest rates are seen in Asian/Pacific
Islanders.
Age: There is a sharp increase in stomach cancer after
the age of 50.
Type A blood: For unknown reasons,
people with type A blood have a higher risk of getting
stomach cancer.
Family history: People with several
close relatives who have had stomach cancer are more
likely to develop this disease. Also, some families
have a gene change (mutation) that puts them at greater
risk for getting colorectal cancer and a slightly higher
risk of stomach cancer.
Stomach polyps: Polyps are small mushroom-like
growths of the lining of the stomach. Most types of
polyps do not increase the risk of stomach cancer. But
one type (adenomatous polyps) sometimes develops into
stomach cancer.
Geography: Stomach cancer is most common
in Japan, China, Southern and Eastern Europe, and South
and Central America. This disease is less common in
Northern and Western Africa, Melanesia, South Central
Asia, and North America.
Epstein-Barr virus: This virus causes
“mono” (infectious mononucleosis). It has
been found in the stomach cancers of some people.
While there are many risk factors for stomach cancer,
we do not know exactly how these factors cause cells
of the stomach to become cancerous. Scientists are trying
to learn how and why certain changes take place in the
lining of the stomach and what part H. pylori plays
in stomach cancer.
They are also looking at how gene changes (mutations)
can cause normal stomach cells to grow abnormally and
form cancers. Most of the gene changes that are linked
to stomach cancer take place after birth. Only a very
few are inherited.
Can Stomach Cancer Be Prevented?
Even though we don’t know the exact cause of stomach,
it is still possible to prevent many cases. Increased
use of refrigeration for food storage (rather than using
salting, pickling, and smoking) and changes in diet
have helped lower the rate of stomach cancer over the
past 60 years.
A diet high in fresh fruits and vegetables can lower
stomach cancer risk. The American Cancer Society recommends
eating at least 5 servings each day of vegetables and
fruits as well as servings of whole grain foods like
breads, cereals, pasta, rice, and beans. Red meats,
especially those high in fat or processed, should be
limited.
Tobacco and alcohol use can increase the risk of stomach
cancer. The American Cancer Society suggests limiting
the use of alcoholic beverages, if you drink at all.
And, of course, if you don’t use tobacco, please
don’t start. If you already do, you should make
every attempt to quit.
It is not yet clear whether people with chronic (on-going)
infection with H. pylori bacteria should be treated
to prevent stomach cancer. In one study, doctors gave
antibiotics to people with H pylori infection and lowered
their rate of getting stomach cancer. This is just an
early study though. More research needs to be done on
this issue.
If you or your doctor thinks you might have H pylori
infection and should be treated, there are several ways
of testing for this. The simplest test is a blood test
that looks for antibodies to H pylori.
Using aspirin or similar drugs may lower the risk of
stomach cancer, as well as colon cancer. However, they
can also cause serious internal bleeding and other problems
in some people. Most doctors think of the lower cancer
risk an added benefit for patients who take these drugs
for other problems, such as arthritis. But they do not
recommend them for the sole purpose of reducing cancer
risk.
In countries where stomach cancer is common, finding
it early may be the best way to improve the chance of
successful treatment and reduce the number of deaths
caused by the disease.
How Is Stomach Cancer Found?
Because stomach cancer is not that common in the United
States, mass screening for the disease has not been
found to be useful. But people at high risk should talk
to their doctors about the benefits of screening.
People who have stomach cancer rarely have symptoms
in the early stages of the disease. This is one of the
reasons why stomach cancer is so hard to find early.
The signs and symptoms of this cancer can include:
• unintended weight loss and lack of appetite
• pain in the area of the stomach (abdominal pain)
• vague discomfort in the abdomen, often above the navel
• a sense of fullness just below the chest bone after
eating a small meal
• heartburn, indigestion, or ulcer-type symptoms
• nausea
• vomiting, with or without blood
• swelling of the abdomen
Of course, many of these symptoms can be caused by conditions
other than cancer. But if you have any of these problems
and they don’t go away, you should check with
your doctor.
If Cancer Is Suspected
If there is any reason to suspect stomach cancer, your
doctor will ask you questions about risk factors and
symptoms and do a complete physical exam. The doctor
will feel your abdomen to see if there is any swelling
that might mean a tumor.
You may need to have further tests to find out if the
disease is really present and if so, to see how far
it has spread. Here are some of the tests that might
be done.
Upper endoscopy (en-dos-kuh-pe): In this test, a thin,
flexible, lighted tube (called an endoscope) is placed
down the patient’s throat. With this tube, the
doctor can see the lining of the esophagus, stomach,
and the first part of the small intestine. If anything
looks not normal, tissue samples can be removed. These
samples are looked at under a microscope to see if cancer
is present and, if so, what type of cancer it is. A
person having this test is made sleepy (sedated) before
it starts, so there should be no discomfort.
Upper GI (gastrointestinal) series:
People having this test drink a liquid containing barium
that coats the lining of the esophagus, stomach, and
first part of the small intestine. Then several x-rays
are taken. Sometimes after drinking the liquid, the
person swallows baking soda crystals, which creates
air in the stomach. This makes the barium coating very
thin so that even small abnormalities will show up.
Ultrasound: For this test, sound waves
are used to produce pictures of internal organs. Most
people know about ultrasound because it is used to create
a picture of the baby during pregnancy. Ultrasound can
also be done with a probe placed into the stomach through
the mouth or nose. In this case, it can help tell how
far the cancer has spread within the stomach or into
nearby tissues and lymph nodes.
CT scan (computed tomography): This
test uses a special x-ray machine that takes pictures
from many angles. The pictures are combined by a computer
to produce detailed cross-sectional images. The CT scan
can help show if and where stomach cancer has spread.
It can also be used to guide a biopsy needle into an
area that might be cancer. The needle is used to take
a small sample of tissue for testing in the lab.
CT scans take longer than regular x-rays and you need
to lie still on a table while they are being done. You
may also have an IV (intravenous) line through which
a contrast "dye" is injected.
PET scan (positron emission tomography):
In this test, a special kind of radioactive sugar is
injected into the patient’s vein. The sugar collects
in areas that have cancer and a scanner can spot these
areas. This test is useful for finding cancer that has
spread beyond the stomach. It may also help in staging
the cancer (see below).
MRI scan (magnetic resonance imaging):
Like CT scans, MRIs display a cross-section of the body.
But MRI uses powerful magnets instead of radiation.
MRI scans also take longer than CT scans—often
up to an hour. A contrast dye might be injected just
as with CT scans, but is used less often. Most doctors
prefer to use CT scans, but sometimes an MRI can provide
more information.
Chest x-rays: These can be used to tell if the cancer
has spread to the lungs.
Laparoscopy (lap-uh-ros-kuh-pe): A
thin, flexible tube is placed into the patient’s
side through a small incision and transmits a picture
of the inside of the abdomen to a video screen. The
doctor can use this before surgery to see if all cancer
can be removed and to spot spread of the cancer.
Lab tests: These may include a blood
test called a complete blood count (CBC) to look for
anemia, and a fecal occult blood test, which looks for
small amounts of blood in the stool.
How Is Stomach Cancer Treated?
No matter what stage of stomach cancer you have, there
is treatment. The choice of treatment you receive depends
on many factors. The place and stage of the tumor are
very important, of course. But other factors include
your age, your overall health, and your personal wishes.
The main treatments for stomach cancer are surgery,
chemotherapy, and radiation therapy. Often the best
approach involves using 2 or more of these treatment
methods. Your recovery is one goal of your cancer care
team. If a cure is not possible, treatment is aimed
at relieving symptoms such as trouble eating, pain,
or bleeding. Before you start treatment it is important
that you understand the goal of your treatment-- whether
it is to cure or to relieve symptoms.
Surgery
Depending on the type and stage of your cancer, surgery
might be used to remove the cancer and that part of
the stomach where it is attached. The surgeon will try
to leave behind as much normal stomach as possible.
At this time, surgery is the only way to cure stomach
cancer. If you have stage 0, I, II, or IIII cancer,
and if you are healthy enough, an attempt should be
made to treat the cancer by completely removing it.
Even if the cancer is too widespread to be completely
removed by surgery, an operation could help prevent
bleeding from the tumor or keep the stomach from becoming
blocked. This type of surgery is known as palliative,
meaning that it relieves or prevents symptoms but is
not expected to cure the cancer.
There are 3 main types of surgery for stomach cancer.
Endoscopic mucosal resection (en-doh-SCAH-pic mew-koh-suhl
re-sek-shun): Resection refers to the removal of a tumor
or part of an organ by cutting it out. With this method,
the cancer is removed through the endoscope. This can
be done only for very early cancers where the chance
of spread to the lymph nodes is very low.
Subtotal (partial) gastrectomy (gas-trek-tuh-me): This
approach can be used if the cancer is in the lower part
of the stomach close to the intestines. Only part of
the stomach is removed, sometimes along with the first
part of the small intestine. Eating is much easier with
this approach rather than when the whole stomach is
removed.
Total gastrectomy: This method is used if the cancer
is in the middle or upper part of the stomach. The surgeon
removes the entire stomach. Because the stomach holds
and digests food, when it is removed a person will fill
up after only a few mouthfuls. To solve this problem,
the surgeon will try to make a new "stomach"
out of intestinal tissue. No matter how effective this
is, people who have had a total gastrectomy can only
eat a small amount of food at a time. Because of this,
they must eat more often.
If surgery is done to cure the cancer, the lymph nodes
and some of the fatty tissue (omentum) around the stomach
are removed as well. If the cancer has spread beyond
the stomach to the spleen, it will be removed too.
Many surgeons believe that the chances of a cure are
better if all of the lymph nodes near the stomach are
removed. But it usually takes a skilled surgeon with
experience in operating on stomach cancer to do this.
It is important to ask your surgeon about his or her
experience in operating on stomach cancer. Because stomach
cancer can also spread to lymph nodes that are farther
away in the abdomen, some doctors believe that these
also must be removed. But not all doctors agree.
Surgery for stomach cancer is very hard to do and can
lead to serious problems. These could include bleeding
from the surgery, blood clots, and damage during the
operation to nearby organs such as the gallbladder and
the pancreas. Rarely, the new connections between the
ends of the stomach and esophagus or small intestine
may not hold together completely and leak. Such complications,
which could be fatal, were more common in the past.
Today, only about 1% to 2% of people die after this
surgery.
Other side effects may develop after recovery from surgery.
These could include heartburn, abdominal pain, especially
after eating, and shortages of some vitamins. The stomach
is important in helping the body absorb certain vitamins.
If some parts of the stomach are removed, the doctor
will prescribe vitamin supplements. Some of these can
only be taken by injection. After stomach surgery, most
people will need to change their diets, eating smaller,
more frequent meals.
It is crucial to talk to your doctor about the surgery
you are going to have. Some surgeons try to leave behind
as much of the stomach as they can so that patients
will have fewer problems later. But the tradeoff is
that the cancer might be more likely to come back. Again,
it’s important that your surgeon be highly skilled
and able to do the most up-to-date operations.
Chemotherapy
Chemotherapy refers to the use of drugs to kill cancer
cells. Usually the drugs are given into a vein or by
mouth. Once the drugs enter the bloodstream, they spread
throughout the body. Chemotherapy is useful in treating
cancer that has spread.
Chemotherapy may be used as the main treatment for stomach
cancer that has spread to distant organs. It is being
studied as an added treatment given either before or
after surgery. So far, studies have found that chemotherapy
may help relieve symptoms for some people, especially
those whose cancer has spread to other areas of the
body. There is also some evidence that chemotherapy
together with radiation therapy may delay the cancer
coming back and extend the life of people with advanced
stomach cancer.
While chemotherapy drugs kill cancer cells, they also
damage some normal cells and this can lead to side effects.
These side effects depend on the type of drugs used,
the amount given, and the length of treatment. You could
experience some of these temporary side effects:
• fatigue
• nausea and vomiting
• diarrhea
• loss of appetite
• hair loss (it grows back after treatment ends)
• mouth sores
• a higher risk of infection caused by a shortage of
white blood cells
• bruising or bleeding after minor cuts caused by a
shortage of blood platelets
• shortness of breath from low red blood cell counts
Most of these side effects go away when treatment is
over. If you have any problems with side effects, be
sure to tell your doctor or nurse, as there are often
ways to help.
Radiation Therapy
Radiation therapy is treatment with high-energy rays
(such as x-rays) to kill or shrink cancer cells. Radiation
coming from a machine outside the body (external radiation)
is the type often used to treat stomach cancer.
After surgery, radiation therapy can be used to kill
very small areas of cancer that cannot be seen and removed
during surgery. Some studies suggest that radiation,
especially when combined with chemotherapy, can delay
or prevent the cancer from coming back after surgery
and may help people to live longer. Radiation can also
be used to ease symptoms such as pain, bleeding, and
trouble eating.
Side effects from radiation therapy can include mild
skin problems, nausea, vomiting, diarrhea, or fatigue.
These usually go away a few weeks after treatment is
finished. Radiation therapy may make the side effects
of chemotherapy worse. Talk with your doctor about these
side effects since there are ways to relieve them.
Stomach Cancer Survival Rates
The 5-year relative survival rate is the percentage
of patients who are alive at least 5 years after the
cancer is found. Those who die of other causes are not
counted. Of course, patients might live more than 5
years after diagnosis. These 5-year survival rates are
based on people with stomach cancer first treated more
than 5 years ago. People treated today may have a more
favorable outlook.
The overall 5-year survival rate of people with stomach
cancer in the United States is about 23%. One reason
for this is that most stomach cancers are found at an
advanced stage. The outlook for survival is better if
the cancer is in the lower part of the stomach than
if it is in the upper part.
While numbers provide an overall picture, keep in mind
that every person’s situation is unique and statistics
can’t predict exactly what will happen in your
case. Talk with your cancer care team if you have questions
about your personal chances of a cure, or how long you
might survive your cancer. They know your situation
best.
Clinical Trials
Studies of promising new treatments are known as clinical
trials. A clinical trial is done only when there is
some reason to believe that the new treatment may be
of value to the patient. Clinical trials are needed
in order to find new and better ways to treat cancer.
Treatments used in clinical trials are often found to
have real benefits. The main questions the researchers
want to answer are:
• Is this treatment helpful?
• Does it work better than the one we're now using?
• What side effects does it cause?
• Do the benefits outweigh the side effects?
• Which patients are most likely to find this treatment
helpful?
Clinical trials are carried out in steps called phases.
Each phase is designed to answer certain questions
Phase I clinical trials look at the
best way to give a new treatment and how much of it
can be given safely. The main purpose of a phase I study
is to test the safety of the new drug.
Phase II clinical trials are designed
to see if the drug works. Patients are given the highest
dose that doesn't cause serious side effects and then
watched closely to see if there is an effect on the
cancer.
Phase III clinical trials compare the
new treatment with standard treatment. Large numbers
of patients are divided into two groups. The control
group receives standard treatment and the other group
receives the new treatment. Everyone is closely watched
to see which treatment is more effective. The study
is stopped if the side effects are too severe or if
one group has much better results than the other.
If you are in a clinical trial, you will have a team
of experts watching your progress very carefully. However,
there are some risks. No one knows in advance if the
treatment will work or exactly what side effects will
occur. That is what the study is designed to find out.
Keep in mind, though, that even standard treatments
have side effects.
Taking part in a clinical trial is completely up to
you. Even after joining a clinical trial, you are free
to drop out of the study at any time, for any reason.
Taking part in the study will not prevent you from getting
other medical care you may need.
Courtesy: www.cancer.org,
Please visit the website for further information
|
