Stomach cancer, also called gastric cancer, begins when cells in the stomach become abnormal and grow uncontrollably. These cells form a growth of tissue, called a tumor. Cancer can begin in any part of the stomach, and it can spread to nearby lymph nodes and other areas of the body, such as the liver, pancreas, colon, lungs, and a woman’s ovaries. Most stomach cancers are a type called adenocarcinoma, which means that the cancer started in the cells that line the inside of the stomach. Other types of cancerous tumors that form in the stomach include lymphoma, gastric sarcoma, and carcinoid tumor, but these are rare.

The stomach is located in the upper abdomen and plays a central role in digesting food. When food is swallowed, it slides down the esophagus, or throat, and enters the stomach. The muscles in the stomach mix the food and release gastric juices that help digest and break down the food. The food then moves into the small intestine for further digestion.

Statistics

In 2009, an estimated 21,130 adults (12,820 men and 8,310 women) in the United States will be diagnosed with stomach cancer. It is estimated that 10,620 deaths (6,320 men and 4,300women) from this disease will occur this year. Most people diagnosed with stomach cancer are in their 60s and 70s.

The five-year relative survival rate (percentage of people who survive at least five years after the cancer is detected, excluding those who die from other diseases) of people with stomach cancer is about 25%. This statistic reflects the fact that most cases of stomach cancer are diagnosed when the cancer has already spread to other parts of the body. If stomach cancer is found before it has spread, the five-year relative survival rate is about 61%.

Cancer survival statistics should be interpreted with caution. These estimates are based on data from thousands of cases of this type of cancer in the United States each year, but the actual risk for a particular individual may differ. It is not possible to tell a person how long he or she will live with stomach cancer. Because the survival statistics are measured in five-year intervals, they may not represent advances made in the treatment or diagnosis of this cancer.

The incidence of stomach cancer varies in different parts of the world. Although it is decreasing in the Western world, it is still one of the most common cancer types worldwide.

Statistics adapted from the American Cancer Society's publication, Cancer Facts & Figures 2009.

Find out more about basic cancer terms used in this section.

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A risk factor is anything that increases a person’s chance of developing cancer. Some risk factors can be controlled, such as smoking, and some cannot be controlled, such as age and family history. Although risk factors can influence the development of cancer, most do not directly cause cancer. Some people with several risk factors never develop cancer, while others with no known risk factors do. However, knowing your risk factors and communicating them to your doctor may help you make more informed lifestyle and health-care choices.

The following factors may raise a person’s risk of developing stomach cancer:

Age. Most cases of stomach cancer occur in people over age 55.

Gender. Men have twice the risk of developing stomach cancer as women.

Family history. People who have a first-degree relative (a parent, child, or sibling) who has had stomach cancer are at increased risk for stomach cancer.

Race. Black people are more likely than white people to develop stomach cancer.

Diet. Eating foods preserved by drying, smoking, salting, or pickling may increase the risk of stomach cancer. Eating fresh fruits and vegetables may help lower the risk.

Bacteria. A common bacterium called Helicobacter pylori, which causes stomach inflammation and ulcers, may increase the risk of stomach cancer. However, most people who are infected with this bacterium never develop stomach cancer.

Previous surgery or health conditions. People who have had stomach surgery or have pernicious anemia (severe decrease in red blood cells) or achlorhydria (absence of hydrochloric acid in the gastric juices, which help digest food) have an increased risk of stomach cancer.

Occupational exposure. Exposure to certain dusts and fumes may increase the risk of developing stomach cancer.

Tobacco and alcohol. Tobacco use and excessive alcohol consumption may increase the risk of developing stomach cancer.

Genetic mutations. Certain inherited genetic disorders, such as hereditary diffuse gastric cancer, hereditary non-polyposis colorectal cancer (HNPCC or Lynch syndrome) and familial adenomatous polyposis (FAP) may increase the risk of stomach cancer.

Obesity. Excess body weight increases a man’s risk of developing stomach cancer. It is not clear whether obesity increases a woman’s risk of stomach cancer.

People with stomach cancer may experience the following symptoms. Sometimes, people with stomach cancer do not show any of these symptoms. Or, these symptoms may be caused by a medical condition that is not cancer. If you are concerned about a symptom on this list, please talk with your doctor.

Stomach cancer is usually not found at an early stage because it often does not cause specific symptoms. When symptoms do occur, they may be vague and can include:

• Indigestion or heartburn
  
  
• Pain or discomfort in the abdomen
  
  
• Nausea and vomiting
  
  
• Diarrhea or constipation
  
  
• Bloating of the stomach after meals
  
  
• Loss of appetite

Symptoms of advanced stomach cancer may include:

• Weakness and fatigue
  
  
• Vomiting blood or having blood in the stool
  
  
• Unexplained weight loss

It is important to remember that these symptoms can also be caused by many other illnesses, such as a stomach virus or an ulcer. People with the symptoms listed above should talk with their doctor.

Doctors use many tests to diagnose cancer and determine if it has metastasized (spread). Some tests may also determine which treatments may be the most effective. For most types of cancer, a biopsy is the only way to make a definitive diagnosis of cancer. If a biopsy is not possible, the doctor may suggest other tests that will help make a diagnosis. Imaging tests may be used to find out whether the cancer has metastasized. Your doctor may consider these factors when choosing a diagnostic test:

• Age and medical condition
• The type of cancer suspected
• Severity of symptoms
• Previous test results

In addition to a physical examination, the following tests may be used to diagnose stomach cancer:

Biopsy. A biopsy is the removal of a small amount of tissue for examination under a microscope. Other tests can suggest that cancer is present, but only a biopsy can make a definite diagnosis. The sample removed from the biopsy is analyzed by a pathologist (a doctor who specializes in interpreting laboratory tests and evaluating cells, tissues, and organs to diagnose disease).

Endoscopy. This test allows the doctor to see the inside of the body. The person may be sedated, and the doctor inserts a thin, lighted, flexible tube called a gastroscope or endoscope through the mouth, down the esophagus, and into the stomach. The doctor can remove a sample of tissue during an endoscopy and check it for evidence of cancer.

Endoscopic ultrasound. This test is similar to an endoscopy, but the gastroscope has a small ultrasound probe on the end that produces an image of the stomach. An ultrasound uses sound waves to create a picture of the internal organs. The ultrasound image helps doctors determine how far the cancer has spread into the stomach and nearby tissue.

X-ray. An x-ray is a picture of the inside of the body. For instance, a chest x-ray can help doctors determine if the cancer has spread to the lungs.

Barium swallow. In a barium swallow, a person swallows a liquid containing barium and a series of x-rays are taken. Barium coats the lining of the esophagus, stomach, and intestines, so tumors or other abnormalities are easier to see on the x-ray.

Computed tomography (CT or CAT) scan. A CT scancreates a three-dimensional picture of the inside of the body with an x-ray machine. A computer then combines these images into a detailed, cross-sectional view that shows any abnormalities or tumors. Sometimes, a contrast medium (a special dye) is injected into a patient’s vein to provide better detail.

Magnetic resonance imaging (MRI).An MRIuses magnetic fields, not x-rays, to produce detailed images of the body. A contrast medium may be injected into a patient’s vein to create a clearer picture.

Positron emission tomography (PET) scan. A PET scan is a way to create pictures of organs and tissues inside the body. A small amount of a radioactive substance is injected into a patient’s body and absorbed by the organs or tissues being studied. This substance gives off energy that is detected by a scanner, which produces the images. This technique is increasingly used to predict the effectiveness of chemotherapy in treating this type of cancer.

To learn more about what to expect during common diagnostic tests, read Cancer.Net: Tests and Procedures.

To learn about the terms used in this section, read the Cancer.Net Feature: Cancer Terms to Know: Newly Diagnosed.

Staging is a way of describing a cancer, such as where it is located, if or where it has spread, and if it is affecting the functions of other organs in the body. Doctors use diagnostic tests to determine the cancer's stage, so staging may not be complete until all of the tests are finished. Knowing the stage helps the doctor to decide what kind of treatment is best and can help predict a patient's prognosis (chance of recovery). There are different stage descriptions for different types of cancer.

One tool that doctors use to describe the stage is the TNM system. This system uses three criteria to judge the stage of the cancer: the tumor itself, the lymph nodes around the tumor, and if the tumor has spread to the rest of the body. The results are combined to determine the stage of cancer for each person. There are five stages: stage 0 (zero) and stages I through IV (one through four). The stage provides a common way of describing the cancer, so doctors can work together to plan the best treatments.

TNM is an abbreviation for tumor (T), node (N), and metastasis (M). Doctors look at these three factors to determine the stage of cancer:

• How large is the primary tumor and where is it located? (Tumor, T)
  
  
• Has the tumor spread to the lymph nodes? (Node, N)
  
  
• Has the cancer metastasized to other parts of the body? (Metastasis, M)

Tumor. Using the TNM system, the “T” plus a letter or number (0 to 4) is used to describe the size and location of the tumor. Some stages are also divided into smaller groups that help describe the tumor in even more detail. Specific tumor stage information is listed below:

TX: The primary tumor cannot be evaluated.

T0 (T plus zero): There is no evidence of a primary tumor in the stomach.

Tis: This stage describes a condition called carcinoma (cancer) in situ. The cancer is found only in cells on the surface of the epithelium (the inner lining of the stomach) and has not spread to any other layers of the stomach.

T1: The tumor has invaded the lamina propria and the submucosa (the inner layers of the wall of the stomach).

T2: The tumor has invaded the muscularis propria (the muscle layer of the stomach) and the subserosa (the outer muscle layers of the stomach).

T2a: The tumor has grown through the muscularis propria.

T2b: The tumor has grown into the serosa (the outer layer of the stomach).

T3: The tumor has grown through the serosa, but the tumor has not invaded structures or organs outside the stomach.

T4: The tumor has invaded structures or organs surrounding the stomach, such as the spleen, colon, or liver.

Node. The “N” in the TNM staging system is for lymph nodes, the tiny, bean-shaped organs that help fight infection. Lymph nodes inside the abdomen are called regional lymph nodes. Lymph nodes in other parts of the body are called distant lymph nodes. The overall prognosis for patients with stomach cancer is based on how many regional lymph nodes show evidence of cancer. If six lymph nodes or less are involved, the prognosis is better than if more than 15 lymph nodes contain cancer cells.

NX: Regional lymph nodes cannot be evaluated.

N0 (N plus zero): The cancer has not spread into the regional lymph nodes.

N1: The cancer has spread to one to six regional lymph nodes.

N2: The cancer has spread to seven to 15 regional lymph nodes.

N3: The cancer has spread to more than 15 regional lymph nodes.

Distant metastasis. The “M” in the TNM system indicates whether the cancer has spread to other parts of the body.

MX: Distant metastasis cannot be evaluated.

M0 (M plus zero): The cancer has not metastasized.

M1: The cancer has spread to another part or parts of the body.

Cancer stage grouping

Doctors assign the stage of the cancer by combining the T, N, and M classifications.

Stage 0: This is also called carcinoma in situ. The cancer is found only on the surface of the epithelium. The cancer has not invaded any other layers of the stomach and is considered an early cancer (Tis, N0, M0).

Stage Ia: The cancer has invaded the inner layer of the wall of the stomach, but the cancer has not spread to any lymph nodes or other organs (T1, N0, M0).

Stage Ib: Stomach cancer is called stage IB in either of these two conditions:

• The cancer has grown into the inner layers of the wall of the stomach and has spread to one to six lymph nodes, but not elsewhere (T1, N1, M0).
  
  
• The cancer has grown into outer muscular layers of the wall of the stomach, but the cancer has not spread to the lymph nodes or other organs (T2a or T2b, N0, M0).

Stage II: Stomach cancer is called stage II in any one of these conditions:

• The cancer has invaded the inner layer of the wall of the stomach and has spread to seven to 15 lymph nodes, but not elsewhere (T1, N2, M0).
  
  
• The cancer has invaded the outer muscular layers of the wall of the stomach and has spread to one to six lymph nodes, but not elsewhere (T2a or T2b, N1, M0).
  
  
• The cancer has grown through the wall of the stomach, but it has not spread to any lymph nodes or surrounding organs (T3, N0, M0).

Stage IIIa: Stomach cancer is called stage IIIA in any one of these conditions:

• The cancer has invaded the outer muscular walls of the stomach and has spread to seven to 15 lymph nodes, but not to other organs (T2a or T2b, N2, M0).
  
  
• The cancer has grown through the wall of the stomach and has spread to one to six lymph nodes, but not to other organs (T3, N1, M0).
  
  
• The cancer has invaded organs or structures surrounding the stomach, but the cancer has not spread into any lymph nodes or other organs (T4, N0, M0).

Stage IIIb: Stomach cancer has grown through the wall of the stomach but has not invaded any surrounding organs. The cancer has spread to seven to 15 lymph nodes (T3, N2, M0).

Stage IV: Stomach cancer is called stage IV in any of these conditions:

• Any distant metastasis to other parts of the body besides the area around the stomach (any T, any N, M1).
  
  
• The cancer has invaded more than 15 lymph nodes, regardless of how deeply the tumor has invaded the wall of the stomach (any T, N3, M0).
  
  
• The cancer has invaded the structures or organs surrounding the stomach and has spread to the lymph nodes (T4, N1 to N3, M0).

Recurrent cancer. Recurrent cancer is cancer that comes back after treatment. It may be a localized recurrence (comes back in the place where it started), or it may be a distant metastasis (comes back in another part of the body).

Used with permission of the American Joint Committee on Cancer (AJCC), Chicago, Illinois. The original source for this material is the AJCC Cancer Staging Manual, Sixth Edition (2002) published by Springer-Verlag New York, www.springer-ny.com.

The Japanese system for staging stomach cancer

Stomach cancer is much more common in Japan (and other parts of Asia and South America) than in the United States. The Japanese have a different method of staging stomach cancer, based on where the affected lymph nodes are located around the stomach. This is different from the U.S. system, which uses the number of nodes and not their location.

Surgery for stomach cancer may be described using the Japanese system. The type of surgery is identified by which lymph nodes are removed in addition to the stomach.

• D0: no lymph nodes were removed
  
  
• D1: the lymph nodes closest to the stomach were removed
  
  
• D2: lymph nodes from a wider area were removed

The treatment of stomach cancer depends on the size and location of the tumor, whether the cancer has spread, and the patient’s overall health. In many cases, a team of doctors, including a gastroenterologist (a doctor who specializes in the function and disorders of the gastrointestinal tract, including the stomach, intestines, and associated organs), surgeon, medical oncologist, and radiation oncologist, will work with the patient to determine the best treatment plan.

This section outlines treatments that are the standard of care (the best treatments available) for this specific type of cancer. Patients are also encouraged to consider clinical trials when making treatment plan decisions. A clinical trial is a research study to test a new treatment to prove it is safe, effective, and possibly better than standard treatment. Your doctor can help you review all treatment options. For more information, visit the Clinical Trials Section.

Stomach cancer may be treated with surgery, radiation therapy, or chemotherapy. Often, a combination of these treatments is used. It can be difficult to cure stomach cancer because it is often not detected until it is at an advanced stage.

Surgery

In early stages (0 or I), when the cancer is still contained within the stomach, treatment usually consists of surgery to remove the affected part of the stomach and nearby lymph nodes. If the cancer has spread to the outer stomach wall or to more than three lymph nodes (stage II), surgery plus either chemotherapy or radiation therapy may be used. The surgeon can perform a subtotal or partial gastrectomy (removal of part of the stomach) or a total gastrectomy (removal of all of the stomach). During a gastrectomy, the surgeon attaches the esophagus directly to the small intestine. In a partial gastrectomy, the surgeon connects the remaining part of the stomach to the esophagus or small intestine. After this surgery, the patient will only be able to eat a small amount of food at a time.

Gastrectomy is major surgery and can have serious complications or side effects. One common side effect is a group of symptoms known as dumping syndrome, which includes cramps, nausea, diarrhea, and dizziness after eating. This happens when food enters the small intestine too fast. The doctor can suggest ways to avoid this and can prescribe medication to help control these symptoms. The symptoms usually disappear in a few months, but in some cases, they may be permanent. Patients who have their entire stomachremoved will need regular injections of vitamin B12 because they will no longer be able to absorb this essential vitamin through their stomach.

Regional lymph nodes are often removed during surgery (lymphadenectomy) because the cancer may have spread to those lymph nodes. There is still debate as to how extensive the lymphadenectomy should be. In Europe and especially in Japan, more lymph nodes are routinely removed than in the United States.

Radiation therapy

Radiation therapy is the use of high-energy x-rays or other particles to kill cancer cells. Patients with stomach cancer usually receive external-beam radiation therapy, which is radiation given from a machine outside the body. Radiation therapy may be used before surgery to shrink the size of the tumor or after surgery to destroy any remaining cancer cells.

Side effects from radiation therapy include fatigue, mild skin reactions, upset stomach, and loose bowel movements. Most side effects go away soon after treatment is finished.

Chemotherapy

Chemotherapy is the use of drugs to kill cancer cells. Systemic chemotherapy is delivered through the bloodstream, targeting cancer cells throughout the body. Chemotherapy can be given by mouth or injection. The goal of chemotherapy can be to destroy cancer remaining after surgery, slow the tumor’s growth, or to reduce cancer-related symptoms.It also may be combined with radiation therapy. Currently, there is no standard chemotherapy treatment plan that is accepted worldwide. Fluorouracil (5-FU, Adrucil) and cisplatin (Platinol) are commonly used drugs in treating stomach cancer.

The side effects of chemotherapy depend on the individual and the dose used, but can include fatigue, risk of infection, nausea and vomiting, loss of appetite, and diarrhea. These side effects usually go away once treatment is finished. 

The medications used to treat cancer are continually being evaluated. Talking with your doctor is often the best way to learn about the medications prescribed for you, their purpose, and their potential side effects or interactions with other medications. Learn more about your prescriptions through Cancer.Net's Drug Information Resources, which provides links to searchable drug databases.

Advanced stomach cancer

Advanced stomach cancer has spread to other areas of the body and is generally treated the same way as earlier stages of the disease, with surgery, chemotherapy, or radiation therapy. Doctors may also use surgery to relieve symptoms and prevent intestinal or stomach blockages. Chemotherapy or radiation therapy can also help relieve symptoms.

To learn about the terms used in this section, read the Cancer.Net Feature: Cancer Terms to Know: During Treatment.

Doctors and scientists are always looking for better ways to treat patients with stomach cancer. A clinical trial is a way to test a new treatment to prove that it is safe, effective, and possibly better than a standard treatment. Patients who participate in clinical trials are among the first to receive new treatments before they are widely available. However, there is no guarantee that the new treatment will be safe, effective, or better than a standard treatment.

Patients decide to participate in clinical trials for many reasons. For some patients, a clinical trial is the best treatment option available. Because standard treatments are not perfect, patients are often willing to face the added uncertainty of a clinical trial in the hope of a better result. Other patients volunteer for clinical trials because they know that finding new drugs and other therapies is the only way to make progress in treating stomach cancer. Even if they do not benefit directly from the clinical trial, their participation may benefit future patients with stomach cancer.

To join a clinical trial, patients must complete a learning process known as informed consent. During informed consent, the doctor should list all of the patient's options, so the person understands how the new treatment differs from the standard treatment. The doctor must also list all of the risks of the new treatment, which may or may not be different than the risks of standard treatment. Finally, the doctor must explain what will be required of each patient in order to participate in the clinical trial, including the number of doctor visits, tests, and the schedule of treatment. Learn more about clinical trials, including patient safety, phases of a clinical trial, deciding to participate in a clinical trial, questions to ask the research team, and links to find cancer clinical trials.

Cancer and its treatment can cause a variety of side effects. However, doctors have made major strides in recent years in reducing pain, nausea and vomiting, and other physical side effects of cancer treatments. Many treatments used today are less intensive but as effective as treatments used in the past. Doctors also have many ways to provide relief to patients when such side effects do occur.

Fear of treatment side effects is common after a diagnosis of cancer, but it may be helpful to know that preventing and controlling side effects is a major focus of your health care team. Before treatment begins, talk with your doctor about possible side effects of the specific treatments you will be receiving. The specific side effects that can occur depend on a variety of factors, including the type of cancer, its location, the individual treatment plan (including the length and dosage of treatment), and the person’s overall health.

Ask your doctor which side effects are most likely to happen (and which are not), when side effects are likely to occur, and how they will be addressed by the health-care team if they do happen. Also, be sure to communicate with the doctor about side effects you experience during and after treatment. For more information on the most common side effects of cancer and different treatments, along with ways to prevent or control them, visit Cancer.Net’s section on Managing Side Effects, based on ASCO’s curriculum.

In addition to physical side effects, there may be psychosocial (emotional and social) effects as well. Learn more about the importance of addressing these needs in Cancer.net’s section on Caring for the Whole Patient.

For more information on late effects or long-term side effects, please read the After Treatment section or talk with your doctor.

After treatment for stomach cancer ends, talk with your doctor about developing a follow-up care plan. This plan may include regular physical examinations and/or medical tests to monitor your recovery for the coming months and years. Follow-up care is particularly important in people treated for stomach cancer with radiation therapy because the late effects of treatment after radiation therapy to the abdomen are not fully known.

People who have been treated for stomach cancer by having their entire stomach removed can live and feed themselves normally, but it is important for them to learn how to eat and take food in after major surgery. Talk with your doctor about this type of rehabilitation.

People recovering from stomach cancer are encouraged to follow established guidelines for good health, such as maintaining a healthy weight, not smoking, eating a balanced diet, and having recommended cancer screening tests. Talk with your doctor to develop a plan that is best for your needs. Moderate physical activity can help rebuild your strength and energy level. Your doctor can help you create an appropriate exercise plan based upon your needs, physical abilities, and fitness level. Learn more about Healthy Living After Cancer.

To learn about the terms used in this section, read the Cancer.Net Feature: Cancer Terms to Know: After Treatment.

Research for stomach cancer is ongoing. The following advances may still be under investigation in clinical trials and may not be approved or available at this time. Always discuss all diagnostic and treatment options with your doctor.

As researchers learn more about the causes of stomach cancer, they are beginning to look at new ways of preventing and treating the disease. New combinations of existing treatments and new ways of using the body’s immune system may soon provide additional options to treat people with stomach cancer.

Chemoprevention. This is the use of drugs or nutrients to lower a person’s risk of developing cancer. Preliminary research indicates that using antibiotics to treat people infected with Helicobacter pylori can prevent changes to stomach cells that may lead to cancer. Doctors are also experimenting with antioxidants, a group of nutrients that may have anticancer effects.

Combination therapy. The combination of chemotherapy, radiation therapy, and surgery may reduce the chance that stomach cancer will return. Doctors may give chemotherapy before surgery (neoadjuvant therapy) or after surgery (adjuvant therapy). Doctors are also exploring the possibility of giving both radiation therapy and chemotherapy before or after surgery.

Chemotherapy improvements. Multidrug chemotherapy combinations are being tested for people with stomach cancer. Taxanes (a group of drugs that includes paclitaxel [Taxol] and docetaxel [Taxotere]), irinotecan (Camptosar), oxaliplatin (Eloxatin), and oral drugs such as S-1 and capecitabine (Xeloda) are drugs that are being combined with other types of chemotherapy.

Cancer vaccines. Vaccines stimulate the patient’s immune system to fight cancer and are being tested for stomach cancer.

Targeted therapies. Targeted therapy is a treatment that targets faulty genes or proteins that contribute to cancer growth and development. A tumor requires angiogenesis (the growth of new blood vessels) to grow. Drugs that block the growth of these new blood vessels are called antiangiogenic drugs. Examples of targeted therapies include gefitinib (Iressa), cetuximab (Erbitux), and bevacizumab (Avastin).

Regular communication with your doctor is important in making informed decisions about your health care. Consider asking the following questions of your doctor:

• What is my diagnosis? What does this mean?
  
  
• What stage is the cancer?
  
  
• Can you explain my pathology report to me?
  
  
• What are my options for treatment?
  
  
• What clinical trials are open to me?
  
  
• What treatment do you recommend? Why?
  
  
• What are the possible side effects of this treatment, both in the short term and the long term?
  
  
• How will this treatment affect my daily life? Will I be able to work, exercise, and perform my usual activities?
  
  
• What follow-up tests will I need, and how often will I need them?
  
  
• What support services are available to me? To my family?

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