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

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 gland 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 node above the collar bone, 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; 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.

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. 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-ray 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 anesthetics 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.

A patient who needs a biopsy may want to ask the doctor some of these questions:

• How long will the procedure take? Will I be awake? Will it hurt?
• How soon will I know the results?
• If I do have cancer, who will talk with me about treatment? When?

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 scan, an ultrasound test, 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.

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