Stomach (Gastric) Cancer Causes, Types, Symptoms, Diagnosis, Treatment, Prevention

Stomach (Gastric) Cancer Causes, Types, Symptoms, Diagnosis, Treatment, Prevention

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.

Stomach (Gastric) Cancer Causes, Types, Symptoms, Diagnosis, Treatment, Prevention

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.

What is Stomach (Gastric) Cancer?

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 collar bone, and the ovaries.

Stomach (Gastric) Cancer Causes, Types, Symptoms, Diagnosis, Treatment, Prevention
Stomach (Gastric) Cancer

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.)

Stomach cancer is still the second biggest killer of all cancers and early detection is vital for survival.

Stomach cancers are classified according to the type of tissue where they originate. The most common type of stomach cancer is adenocarcinoma, which starts in the glandular tissue of the stomach and accounts for 90% to 95% of all stomach cancers. Other forms of stomach cancer include lymphomas, which involve the lymphatic system and sarcomas, which involve the connective tissue (such as muscle, fat, or blood vessels).

If you have the slightest suspicion of any of the symptoms mentioned, you should contact your doctor at once for an assessment.

Types of Stomach (Gastric) Cancer

About nine in 10 stomach cancers are adenocarcinomas. This type of stomach cancer starts in the glandular cells that produce mucus and stomach juices.

Other, rarer, types of stomach cancer include:

  • squamous cell carcinomas, where the cancer starts in squamous cells (skin-like cells that make up part of your stomach lining)
  • soft tissue sarcomas, where the cancer starts in the muscle layer of your stomach wall
  • lymphomas, where the cancer starts in your lymphatic system
  • carcinoid tumours, where the cancer starts in your neuroendocrine system (the system of glands throughout your body that produce hormones)

What Causes Stomach (Gastric) Cancer?

The exact cause of stomach cancer is unknown, but a number of factors can increase the risk of the disease, including:

Gender -- men have more than double the risk of getting stomach cancer than women.

Race -- being African-American or Asian may increase your risk.

Genetics -- genetic abnormalities and some inherited cancer syndromes may increase your risk

Geography -- stomach cancer is more common in Japan, the former Soviet Union, and parts of Central America and South America.

Blood type -- individuals with blood group A may be at increased risk.

Advanced age -- stomach cancer occurs more often around ages 70 and 74 in men and women, respectively.

Family history of gastric cancer can double or triple the risk of stomach cancer.

Lifestyle factors such as smoking, drinking alcohol, and eating a diet low in fruits and vegetables or high in salted, smoked, or nitrate-preserved foods may increase your risk.

Helicobacter pylori (H. pylori) infection of the stomach. H. pylori is a bacterium that infects the lining of the stomach and causes chronic inflammation and ulcers.

Certain health conditions including chronic gastritis, pernicious anemia, gastric polyps, intestinal metaplasia, and prior stomach surgery.

Work-related exposure due to coal mining, nickel refining, and rubber and timber processing and asbestos exposure.

Blood group A. People who have this blood group have a slightly higher risk.

What Are the Symptoms of Stomach (Gastric) Cancer?

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 (Gastric) Cancer Causes, Types, Symptoms, Diagnosis, Treatment, Prevention
Stomach (Gastric) Cancer

In the early stages of stomach cancer, you may have very few symptoms. These may include:

  • Indigestion and stomach discomfort
  • A bloated feeling after eating
  • Mild nausea
  • Loss of appetite
  • Heartburn
  • Diarrhea or constipation
These symptoms are similar to those caused by a peptic ulcer. If you are experiencing any of these symptoms you should see your health care provider so that a proper diagnosis can be made and timely treatment given. A stomach cancer can grow very large before it causes other symptoms.

In more advanced cancer, you may have:

  • Discomfort in the upper or middle part of the abdomen.
  • Blood in the stool (which appears as black, tarry stools).
  • Vomiting or vomiting blood.
  • Weight loss.
  • Pain or bloating in the stomach after eating.
  • Weakness or fatigue associated with mild anemia (a deficiency in red blood cells).

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 for Stomach (Gastric) Cancer

To determine if any of the above are stomach cancer 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.


 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.

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?

How Is Stomach (Gastric) Cancer staged?

Staging is a tool used by doctors to determine the extent of the disease as well as the best treatment options available.

It also gives an indication of prognosis or survival.

To stage stomach cancer, the main investigation used is a CT or computerised tomography scan.

CT provides fine detail of your organs and allows your doctor to check the rest of your body for evidence of cancer spread.

Sometimes, a different type of gastroscopy called an endoultrasound test is performed after the tumour has been diagnosed.

An endoultasound is carried out in the same way as a gastroscopy, but with the addition of a special ultrasound probe on the tip of the gastroscope.

This allows your doctor to determine the depth of invasion of the tumour as well as evidence of spread outside of the stomach,

Stomach (Gastric) Cancer 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.

Many people who have cancer want to learn all they can about the disease and their treatment choices so they can take an active part in decisions about their medical care. The doctor is the best person to answer questions about their diagnosis and treatment plan.

When a person is diagnosed with cancer, shock and stress are natural reactions. These feelings may make it difficult for people to think of everything they want to ask the doctor. Often, it helps to make a list of questions. Also, to help remember what the doctor says, patients may take notes or ask whether they may use a tape recorder. Some people also want to have a family member or friend with them when they talk to the doctor -- to take part in the discussion, to take notes, or just to listen. Patients should not feel the need to ask all their questions or remember all the answers at one time. They will have other chances to ask the doctor to explain things and to get more information.

When talking about treatment choices, the patient may want to ask about taking part in a research study.

These are some questions a patient may want to ask the doctor before treatment begins:

  • What is the stage of the disease?
  • What are my treatment options? Which do you suggest for me? Why?
  • Would a clinical trial be appropriate for me?
  • What are the expected benefits of the treatment?
  • What are the risks and possible side effects of the treatment?
  • What can be done about side effects?
  • What can I do to take care of myself during therapy?
  • How long will my treatment last?

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 two 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.

Stomach (Gastric) Cancer Treatment Methods

Cancer of the stomach is difficult to cure unless it is found in an early stage (before it has begun to spread). Unfortunately, because stomach cancer symptoms in the early stages tend to be few, 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.

These are some questions a patient may want to ask the doctor before surgery:

  • What kind of operation will I have?
  • What are the risks of this operation?
  • How will I feel afterwards? If I have pain, how will you help me?
  • Will I need a special diet? Who will teach me about my diet?


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.

These are some questions patients may want to ask about chemotherapy:

  • What is the goal of this treatment?
  • What drugs will I be taking?
  • Will the drugs cause side effects? What can I do about them?
  • How long will I need to take this treatment?
  • How will we know if the treatment is working?

Radiation therapy

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.

These are some questions a patient may want ask the doctor before receiving radiation therapy:

  • What is the goal of this treatment?
  • How will the radiation be given?
  • When will the treatment begin? When will it end?
  • Will I have side effects? What can I do about them?
  • How will we know if the radiation therapy is working?

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.

Clinical Trials

Many patients with stomach cancer are treated in clinical trials (treatment studies). Doctors conduct clinical trials to find out whether a new approach is both safe and effective and to answer scientific questions. Patients who take part in these studies are often the first to receive treatments that have shown promise in laboratory research. In clinical trials, some patients may receive the new treatment while others receive the standard approach. In this way, doctors can compare different therapies. Patients who take part in a trial make an important contribution to medical science and may have the first chance to benefit from improved treatment methods. Researchers also use clinical trials to look for ways to reduce the side effects of treatment and to improve the quality of patients' lives.

Many clinical trials for people with stomach cancer are under way. Patients who are interested in taking part in a trial should talk with their doctor.

One way to learn about clinical trials is through PDQ, a computer database developed by the National Cancer Institute. PDQ contains information about cancer treatment and about clinical trials. The Cancer Information Service can provide PDQ information to doctors, patients, and the public.

Side Effects of Treatment of Stomach (Gastric) Cancer

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.


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 stomach cancer 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.


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.

Prevention of Stomach (Gastric) Cancer

Some simple dietary changes can reduce your risk of stomach cancer. For example, you should:

  • eat a healthy diet with at least five portions of fruit and vegetables a day
  • cut down on processed and pickled foods
  • reduce your intake of salt and red meat
  • not smoke or chew tobacco
  • only drink alcohol in moderation
  • maintain a healthy weight
Talk to your GP if you need further advice and information.

What Is the Prognosis for People With Stomach (Gastric) Cancer?

Stomach cancer is difficult to cure unless it is found at an early stage before it has spread. Unfortunately, because early stomach cancer has 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.

How do I go about getting a second opinion

Before starting treatment, you might want a second opinion from another doctor about your diagnosis and treatment plan. Some people worry that their doctor will be offended if they ask for a second opinion. Usually the opposite is true. Most doctors welcome a second opinion. And many health insurance companies will pay for a second opinion if you or your doctor requests it. Some companies require a second opinion.

If you get a second opinion, the doctor may agree with your first doctor's diagnosis and treatment plan. Or the second doctor may suggest another approach. Either way, you'll have more information and perhaps a greater sense of control. You may also feel more confident about the decisions you make, knowing that you've looked carefully at your options.

It may take some time and effort to gather your medical records and see another doctor. Usually it's not a problem if it takes you several weeks to get a second opinion. In most cases, the delay in starting treatment will not make treatment less effective. To make sure, you should discuss this possible delay with your doctor. Some people with stomach cancer need treatment right away.

There are many ways to find a doctor for a second opinion. You can ask your doctor, a local or state medical society, a nearby hospital, or a medical school for names of specialists.

Nutrition for Stomach (Gastric) Cancer Patients

It is sometimes difficult for patients who have been treated for stomach cancer to eat well. Cancer often causes loss of appetite, and people may not feel like eating when they are uncomfortable or tired. It is hard for patients to eat when they have nausea, vomiting, mouth sores, or the dumping syndrome. Patients who have had stomach surgery are likely to feel full after eating only a small amount of food. For some patients, the taste of food changes. Still, good nutrition is important. Eating well means getting enough calories and protein to help prevent weight loss, regain strength, and rebuild normal tissues.

Doctors, nurses, and dietitians can offer advice for healthy eating during and after cancer treatment.

Support for Stomach (Gastric) Cancer Patients

Living with a serious disease is not easy. Cancer patients and those who care about them face many problems and challenges. Coping with these problems is often easier when people have helpful information and support services.

Cancer patients may worry about holding their job, caring for their family, or keeping up with their daily activities. Concerns about tests, treatments, hospital stays, and medical bills are common. Doctors, nurses, and other members of the health care team can answer questions about treatment, working, or other activities. Meeting with a social worker, counselor, or member of the clergy also can be helpful for patients who want to talk about their feelings or discuss their concerns about the future or about personal relationships.

Friends and relatives can be very supportive. Also, it helps many patients to discuss their concerns with others who have cancer. Cancer patients often get together in support groups, where they can share what they have learned about coping with cancer and the effects of treatment. It is important to keep in mind, however, that each patient is different. Treatments and ways of dealing with cancer that work for one person may not be right for another -- even if they both have the same kind of cancer. It is always a good idea to discuss the advice of friends and family members with the doctor.

Often, a social worker at the hospital or clinic can suggest groups that can help with rehabilitation, emotional support, financial aid, transportation, or home care. For example, the American Cancer Society has many services for cancer patients and their families. Local offices of the American Cancer Society are listed in the white pages of the telephone directory. The Cancer Information Service also has information on local resources.