Each year, about 24,000 people in the United States learn that they have cancer of the stomach.

The stomach cancer rate in the United States, and the number of deaths from this disease, has 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.

Causes of Stomach Cancer

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
• To affect men twice as often as women
• To be 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.

Some studies suggest that a certain 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.

People who think they might be at risk for stomach cancer should discuss this concern with their doctor. The doctor can suggest an appropriate schedule of checkups so that, if cancer appears, it can be detected as early as possible.

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.

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.)

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
• 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.

Diagnosis

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. Placing a small amount of stool on a plastic slide or on special paper does this test. 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, non-cancerous 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.

For questions to ask your doctor regarding your medical care, see the section titled Questions To Ask Your Doctor found in After The Diagnosis.

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 will depend on these findings.

Treatment

The doctor develops a treatment plan to fit each patient's needs. Treatment for stomach cancer depends on the size, location, and extent of the tumor, the stage of the disease, the patient's general health, and other factors.

Patients and their loved ones are naturally concerned about the effectiveness of the treatment. Sometimes they use statistics to try to figure out whether the patient will be cured, or how long he or she will live. It is important to remember, however, that statistics are averages based on large numbers of patients. They cannot be used to predict what will happen to a particular person because no 2 cancer patients are alike; treatments and responses vary greatly. Patients may want to talk with the doctor about the chance of recovery (prognosis). When doctors talk about surviving cancer, they may use the term remission rather than cure. Even though many patients recover completely, doctors use this term because the disease can return. (The return of cancer is called a recurrence.)

Methods of 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.

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.

The patient goes to the hospital or clinic each day for radiation therapy. Usually treatments are given 5 days a week for 5 to 6 weeks.

Biological therapy (also called immunotherapy) is a form of treatment that helps the body's immune system attack and destroy cancer cells; it may also help the body recover from some of the side effects of treatment.

In clinical trials, doctors are studying biological therapy in combination with other treatments to try to prevent a recurrence of stomach cancer. In another use of biological therapy, patients who have low blood cell counts during or after chemotherapy may receive colony-stimulating factors to help restore the blood cell levels. Patients may need to stay in the hospital while receiving some types of biological therapy.

Researchers continue to look for better ways to diagnose and treat cancer of the stomach, and their knowledge is growing.

Information extracted from www.cancer.gov, What You Need To Know About Stomach Cancer, NIH Publication No. 94-1554. Call the NCI-supported Cancer Information Service (CIS) toll-free at 1-800-4-CANCER (1-800-422-6237) to obtain a copy, or through the Cancer Support Services Office of the HealthCare Consortium at 822-8820.