Gastric cancer
Gastric cancer is a disease in which malignant (cancer) cells form in the lining of the
stomach.
The stomach is a J-shaped organ in the upper abdomen. It is part of the digestive system, which
processes nutrients (vitamins, minerals, carbohydrates, fats, proteins, and water) in foods that are eaten
and helps pass waste material out of the body. Food moves from the throat to the stomach through a
hollow, muscular tube called the esophagus. After leaving the stomach, partly-digested food passes into
the small intestine and then into the large intestine.
The stomach and esophagus are part of the upper
digestive system.
The wall of the stomach is made up of 3 layers of tissue: the mucosal (innermost) layer, the muscularis
(middle) layer, and the serosal (outermost) layer. Gastric cancer begins in the cells lining the mucosal
layer and spreads through the outer layers as it grows.
Stromal tumors of the stomach begin in supporting connective tissue and are treated differently from
gastric cancer.
Age, diet, and stomach disease can affect the risk of developing gastric cancer.
Anything that increases your risk of getting a disease is called a risk factor. Having a risk factor does not
mean that you will get cancer; not having risk factors doesn't mean that you will not get cancer. People
who think they may be at risk should discuss this with their doctor. Risk factors for gastric cancer include
the following:
- Having any of the following medical conditions:
- Helicobacter pylori (H. pylori) infection of the stomach.
- Chronic gastritis (inflammation of the stomach).
- Pernicious anemia.
- Intestinal metaplasia (a condition in which the normal stomach lining is replaced with the
cells that line the intestines).
- Familial adenomatous polyposis (FAP) or gastric polyps.
- Eating a diet high in salted, smoked foods and low in fruits and vegetables.
- Eating foods that have not been prepared or stored properly.
- Being older or male.
- Smoking cigarettes.
- Having a mother, father, sister, or brother who has had stomach cancer.
Possible signs of gastric cancer include indigestion and stomach discomfort or pain.
These and other symptoms may be caused by gastric cancer. Other conditions may cause the same
symptoms.
In the early stages of gastric cancer, the following symptoms may occur:
- Indigestion and stomach discomfort.
- A bloated feeling after eating.
- Mild nausea.
- Loss of appetite.
- Heartburn.
In more advanced stages of gastric cancer, the following symptoms may occur:
- Blood in the stool.
- Vomiting.
- Weight loss for no known reason.
- Stomach pain.
- Jaundice (yellowing of eyes and skin).
- Ascites (build-up of fluid in the abdomen).
- Trouble swallowing.
A doctor should be consulted if any of these problems occur.
Tests that examine the stomach and esophagus are used to detect (find) and
diagnose gastric cancer.
The following tests and procedures may be used:
- Physical exam and history: An exam of the body to check general signs of health, including
checking for signs of disease, such as lumps or anything else that seems unusual. A history of the
patient’s health habits and past illnesses and treatments will also be taken.
- Blood chemistry studies: A procedure in which a blood sample is checked to measure the
amounts of certain substances released into the blood by organs and tissues in the body. An
unusual (higher or lower than normal) amount of a substance can be a sign of disease in the organ
or tissue that produces it.
- Complete blood count (CBC): A procedure in which a sample of blood is drawn and checked for
the following:
- The number of red blood cells, white blood cells, and platelets.
- The amount of hemoglobin (the protein that carries oxygen) in the red blood cells.
- The portion of the sample made up of red blood cells.
Upper endoscopy: A procedure to look inside the esophagus, stomach, and duodenum (first part
of the small intestine) to check for abnormal areas. An endoscope (a thin, lighted tube) is passed
through the mouth and down the throat into the esophagus.
Upper endoscopy. A thin, lighted tube is inserted
through the mouth to look for abnormal areas in the
esophagus, stomach, and first part of the small
intestine.
Fecal occult blood test: A test to check stool (solid waste) for blood that can only be seen with a
microscope. Small samples of stool are placed on special cards and returned to the doctor or
laboratory for testing.
Barium swallow: A series of x-rays of the esophagus and stomach. The patient drinks a liquid that
contains barium (a silver-white metallic compound). The liquid coats the esophagus and stomach,
and x-rays are taken. This procedure is also called an upper GI series.
Barium swallow. The patient swallows barium liquid
and it flows through the esophagus and into the
stomach. X-rays are taken to look for abnormal
areas.
Biopsy: The removal of cells or tissues so they can be viewed under a microscope to check for
signs of cancer. A biopsy of the stomach is usually done during the endoscopy.
CT scan (CAT scan): A procedure that makes a series of detailed pictures of areas inside the
body, taken from different angles. The pictures are made by a computer linked to an x-ray machine.
A dye may be injected into a vein or swallowed to help the organs or tissues show up more clearly.
This procedure is also called computed tomography, computerized tomography, or computerized
axial tomography.
Certain factors affect prognosis (chance of recovery) and treatment options.
The prognosis (chance of recovery) and treatment options depend on the following:
- The stage and extent of the cancer (whether it is in the stomach only or has spread to lymph
nodes or other places in the body).
- The patient’s general health.
When gastric cancer is found very early, there is a better chance of recovery. Gastric cancer is often in an
advanced stage when it is diagnosed. At later stages, gastric cancer can be treated but rarely can be
cured. Taking part in one of the clinical trials being done to improve treatment should be considered.
After gastric cancer has been diagnosed, tests are done to find out if cancer cells
have spread within the stomach or to other parts of the body.
The process used to find out if cancer has spread within the stomach or to other parts of the body is
called staging. The information gathered from the staging process determines the stage of the disease. It
is important to know the stage in order to plan treatment.
The following tests and procedures may be used in the staging process:
- β-hCG (beta-human chorionic gonadotropin), CA-125, and CEA (carcinoembryonic antigen)
assays: Tests that measure the levels of β-hCG, CA-125, and CEA in the blood. These substances
are released into the bloodstream from both cancer cells and normal cells. When found in higher
than normal amounts, they can be a sign of gastric cancer or other conditions.
- Chest x-ray: An x-ray of the organs and bones inside the chest. An x-ray is a type of energy beam
that can go through the body and onto film, making a picture of areas inside the body.
- Endoscopic ultrasound (EUS): A procedure in which an endoscope is inserted into the body,
usually through the mouth or rectum. An endoscope is a thin, tube-like instrument with a light and a
lens for viewing. A probe at the end of the endoscope is used to bounce high-energy sound waves
(ultrasound) off internal tissues or organs and make echoes. The echoes form a picture of body
tissues called a sonogram. This procedure is also called endosonography.
- CT scan (CAT scan): A procedure that makes a series of detailed pictures of areas inside the
body, taken from different angles. The pictures are made by a computer linked to an x-ray machine.
A dye may be injected into a vein or swallowed to help the organs or tissues show up more clearly.
This procedure is also called computed tomography, computerized tomography, or computerized
axial tomography.
- Laparoscopy: A surgical procedure to look at the organs inside the abdomen to check for signs of
disease. Small incisions (cuts) are made in the wall of the abdomen and a laparoscope (a thin,
lighted tube) is inserted into one of the incisions. Other instruments may be inserted through the
same or other incisions to perform procedures such as removing organs or taking tissue samples for
biopsy.
- PET scan (positron emission tomography scan): A procedure to find malignant tumor cells in the
body. A small amount of radioactive glucose (sugar) is injected into a vein. The PET scanner rotates
around the body and makes a picture of where glucose is being used in the body. Malignant tumor
cells show up brighter in the picture because they are more active and take up more glucose than
normal cells do.
There are three ways that cancer spreads in the body.
The three ways that cancer spreads in the body are:
- Through tissue. Cancer invades the surrounding normal tissue.
- Through the lymph system. Cancer invades the lymph system and travels through the lymph
vessels to other places in the body.
- Through the blood. Cancer invades the veins and capillaries and travels through the blood to
other places in the body.
When cancer cells break away from the primary (original) tumor and travel through the lymph or blood to
other places in the body, another (secondary) tumor may form. This process is called metastasis. The
secondary (metastatic) tumor is the same type of cancer as the primary tumor. For example, if breast
cancer spreads to the bones, the cancer cells in the bones are actually breast cancer cells. The disease
is metastatic breast cancer, not bone cancer.
The following stages are used for gastric cancer:
Stage 0 (Carcinoma in Situ)
In stage 0, abnormal cells are found in the inside lining of the mucosal (innermost) layer of the stomach
wall. These abnormal cells may become cancer and spread into nearby normal tissue. Stage 0 is also
called carcinoma in situ.
Stage I
In stage I, cancer has formed. Stage I is divided into stage IA and stage IB, depending on where the
cancer has spread.
- Stage IA: Cancer has spread completely through the mucosal (innermost) layer of the stomach
wall.
- Stage IB: Cancer has spread:
- completely through the mucosal (innermost) layer of the stomach wall and is found in up
to 6 lymph nodes near the tumor; or
- to the muscularis (middle) layer of the stomach wall.
Stage II
In stage II gastric cancer, cancer has spread:
- completely through the mucosal (innermost) layer of the stomach wall and is found in 7 to 15
lymph nodes near the tumor; or
- to the muscularis (middle) layer of the stomach wall and is found in up to 6 lymph nodes near the
tumor; or
- to the serosal (outermost) layer of the stomach wall but not to lymph nodes or other organs.
Stage III
Stage III gastric cancer is divided into stage IIIA and stage IIIB depending on where the cancer has
spread.
- Stage IIIA: Cancer has spread to:
- the muscularis (middle) layer of the stomach wall and is found in 7 to 15 lymph nodes
near the tumor; or
- the serosal (outermost) layer of the stomach wall and is found in 1 to 6 lymph nodes near
the tumor; or
- organs next to the stomach but not to lymph nodes or other parts of the body.
Stage IIIB: Cancer has spread to the serosal (outermost) layer of the stomach wall and is found in
7 to 15 lymph nodes near the tumor.
Stage IV
In stage IV, cancer has spread to:
- organs next to the stomach and to at least one lymph node; or
- more than 15 lymph nodes; or
- other parts of the body.
Recurrent Gastric Cancer
Recurrent gastric cancer is cancer that has recurred (come back) after it has been treated. The
cancer may come back in the stomach or in other parts of the body such as the liver or lymph
nodes.
There are different types of treatment for patients with gastric cancer.
Different types of treatments are available for patients with gastric cancer. Some treatments are standard
(the currently used treatment), and some are being tested in clinical trials. A treatment clinical trial is a
research study meant to help improve current treatments or obtain information on new treatments for
patients with cancer. When clinical trials show that a new treatment is better than the standard treatment,
the new treatment may become the standard treatment. Patients may want to think about taking part in a
clinical trial. Some clinical trials are open only to patients who have not started treatment.
Four types of standard treatment are used:
Surgery
Surgery is a common treatment of all stages of gastric cancer. The following types of surgery may be
used:
- Subtotal gastrectomy: Removal of the part of the stomach that contains cancer, nearby lymph
nodes, and parts of other tissues and organs near the tumor. The spleen may be removed. The
spleen is an organ in the upper abdomen that filters the blood and removes old blood cells.
- Total gastrectomy: Removal of the entire stomach, nearby lymph nodes, and parts of the
esophagus, small intestine, and other tissues near the tumor. The spleen may be removed. The
esophagus is connected to the small intestine so the patient can continue to eat and swallow.
If the tumor is blocking the stomach but the cancer cannot be completely removed by standard surgery,
the following procedures may be used:
- Endoluminal stent placement: A procedure to insert a stent (a thin, expandable tube) in order to
keep a passage (such as arteries or the esophagus) open. For tumors blocking the passage into or
out of the stomach, surgery may be done to place a stent from the esophagus to the stomach or
from the stomach to the small intestine to allow the patient to eat normally.
- Endoluminal laser therapy: A procedure in which an endoscope (a thin, lighted tube) with a laser
attached is inserted into the body. A laser is an intense beam of light that can be used as a knife.
Chemotherapy
Chemotherapy is a cancer treatment that uses drugs to stop the growth of cancer cells, either by killing
the cells or by stopping them from dividing. When chemotherapy is taken by mouth or injected into a vein
or muscle, the drugs enter the bloodstream and can reach cancer cells throughout the body (systemic
chemotherapy). When chemotherapy is placed directly into the spinal column, an organ, or a body cavity
such as the abdomen, the drugs mainly affect cancer cells in those areas (regional chemotherapy). The
way the chemotherapy is given depends on the type and stage of the cancer being treated.
Radiation therapy
Radiation therapy is a cancer treatment that uses high-energy x-rays or other types of radiation to kill
cancer cells or keep them from growing. There are two types of radiation therapy. External radiation
therapy uses a machine outside the body to send radiation toward the cancer. Internal radiation therapy
uses a radioactive substance sealed in needles, seeds, wires, or catheters that are placed directly into or
near the cancer. The way the radiation therapy is given depends on the type and stage of the cancer
being treated.
Chemoradiation
Chemoradiation combines chemotherapy and radiation therapy to increase the effects of both.
Chemoradiation treatment given after surgery to increase the chances of a cure is called adjuvant
therapy. If it is given before surgery, it is called neoadjuvant therapy.
New types of treatment are being tested in clinical trials.
This summary section describes treatments that are being studied in clinical trials. It may not mention every new
treatment being studied.
Patients may want to think about taking part in a clinical trial.
For some patients, taking part in a clinical trial may be the best treatment choice. Clinical trials are part of
the cancer research process. Clinical trials are done to find out if new cancer treatments are safe and
effective or better than the standard treatment.
Many of today's standard treatments for cancer are based on earlier clinical trials. Patients who take part
in a clinical trial may receive the standard treatment or be among the first to receive a new treatment.
Patients who take part in clinical trials also help improve the way cancer will be treated in the future. Even
when clinical trials do not lead to effective new treatments, they often answer important questions and
help move research forward.
Patients can enter clinical trials before, during, or after starting their cancer
treatment.
Some clinical trials only include patients who have not yet received treatment. Other trials test treatments
for patients whose cancer has not gotten better. There are also clinical trials that test new ways to stop
cancer from recurring (coming back) or reduce the side effects of cancer treatment.
Clinical trials are taking place in many parts of the country.
Follow-up tests may be needed.
Some of the tests that were done to diagnose the cancer or to find out the stage of the cancer may be
repeated. Some tests will be repeated in order to see how well the treatment is working. Decisions about
whether to continue, change, or stop treatment may be based on the results of these tests. This is
sometimes called re-staging.
Some of the tests will continue to be done from time to time after treatment has ended. The results of
these tests can show if your condition has changed or if the cancer has recurred (come back). These
tests are sometimes called follow-up tests or check-ups.
Treatment Options by Stage
Stage 0 (Carcinoma in Situ)
Treatment of stage 0 is usually surgery (total or subtotal gastrectomy).
Stage I Gastric Cancer
Treatment of stage I gastric cancer may include the following:
- Surgery (total or subtotal gastrectomy).
- Surgery (total or subtotal gastrectomy) followed by chemoradiation therapy.
- A clinical trial of chemoradiation therapy given before surgery.
Stage II Gastric Cancer
Treatment of stage II gastric cancer may include the following:
- Surgery (total or subtotal gastrectomy).
- Surgery (total or subtotal gastrectomy) followed by chemoradiation therapy.
- Chemotherapy given before and after surgery.
- A clinical trial of surgery followed by chemoradiation therapy testing new anticancer drugs.
- A clinical trial of chemoradiation therapy given before surgery.
Stage III Gastric Cancer
Treatment of stage III gastric cancer may include the following:
- Surgery (total gastrectomy).
- Surgery followed by chemoradiation therapy.
- Chemotherapy given before and after surgery.
- A clinical trial of surgery followed by chemoradiation therapy testing new anticancer drugs.
- A clinical trial of chemoradiation therapy given before surgery.
Stage IV Gastric Cancer
Treatment of stage IV gastric cancer that has not spread to distant organs may include the following:
- Surgery (total gastrectomy).
- Surgery followed by chemoradiation therapy.
- Chemotherapy given before and after surgery.
- A clinical trial of surgery followed by chemoradiation therapy testing new anticancer drugs.
- A clinical trial of chemoradiation therapy given before surgery.
Treatment of stage IV gastric cancer that has spread to distant organs may include the following:
- Chemotherapy as palliative therapy to relieve symptoms and improve the quality of life.
- Endoluminal laser therapy or endoluminal stent placement to relieve a blockage in the stomach.
- Radiation therapy as palliative therapy to stop bleeding, relieve pain, or shrink a tumor that is
blocking the stomach.
- Surgery as palliative therapy to stop bleeding or shrink a tumor that is blocking the stomach.
- A clinical trial of new combinations of chemotherapy as palliative therapy to relieve symptoms and
improve the quality of life.
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