The stomach is part of the digestive system. It is a muscular sac located at the top of the abdomen, just below the ribs, between the chest and the hips. After food is chewed and swallowed, it moves from the mouth through the esophagus, and into the stomach. Once in the stomach, the food mixes with gastric juice to begin the digestive process. The muscles within the stomach then push the liquid into the small intestine.
Another term for stomach cancer is gastric cancer. It is a malignant tumor that forms in the tissues in the lining of the stomach. The cancer can start in any section of the stomach. Symptoms, treatment options and survival outlook depend on the location of the cancer in the stomach.
The wall of the stomach consists of five layers. As the cancer grows deeper into the wall the outlook diminishes. The cancer can spread over time, deeper into the stomach wall. A stomach tumor can eventually grow through the stomach’s outer layer and extend into other organs such as the pancreas, esophagus, liver, and intestine. lungs and lymph nodes. The distant spread of cancer is called metastasis. The five layers of the stomach, starting from the inside out are:
- Mucosa – This is the innermost layer and where most stomach cancers begin. The juices produced by the glands in this inner layer help digest food.
- Submucosa – This is the next layer and the support tissue for the inner layer.
- Muscularis – This layer of muscle moves and mixes the contents of the stomach.
- Subserosa – This layer is the support tissue for the outer layer.
- Serosa – This outermost layer acts as a wrapping for the stomach.
Stomach cancer can develop in any part of the stomach and is typically develops slowly over several years. Pre-cancerous changes occur in the lining of the stomach before a cancer develops. These early changes rarely cause symptoms and it is for that reason that stomach cancer is rarely detected in the early stages.
While stomach cancer is common worldwide, it is uncommon in the United States. Over the past 60 years there has been a significant decrease in the number of people diagnosed with this and the numbers continue to decline. This is mainly attributed to the fact that people in this country are eating less salted, cured and smoked food and the increased use of refrigeration for food storage. Some doctors also attribute the decline in stomach cancers in the United States to the use of antibiotics to treat infections. These
antibiotics kill the H. Pylori bacteria which may be a major cause of stomach cancer. When diagnosed and treated in its early stage, stomach cancer can often be cured. If it is in a more advanced stage when it is discovered the outlook can become less favorable.
The cancers are classified according to the type of tissue from which they originate. When the term stomach cancer is used it is generally referring to adenocancarcinoma since the other forms are stomach cancer are rare.
The different types of stomach cancer include:
- Adenocancarcinoma – This is the most common form of stomach cancer and it accounts for 90% to 95% of the cases. This cancer starts in the glandular tissue of the stomach in the cells that the innermost lining.
- Lymphoma – This stomach cancer involves the lymphatic system and is a rare form of the disease. The walls of the stomach contain a few immune system cells that can develop cancer.
- Carcinoid Cancer – This is a rare form of stomach cancer that develops in hormone producing cells.
- Gastrointestinal Stromal Tumor (GIST) – GIST is also a rare form of stomach cancer that begins in specific nervous system cells that are found in the stomach.
Cancer begins in cells that are the building blocks that make up tissues. Tissues then make up the various organs in the body. When the body requires it, new cells are formed as normal cells grow and divide. When normal cells get old or damaged, they will die, and new cells will take their place. There are times when the process goes wrong. New cells may form when the body doesn’t require them, and old and damaged cells will not die, as they should. A mass of tissue called a growth (nodule or tumor) is formed as a result of the buildup of these extra cells. These growths can be benign or malignant.
Stomach cancer can spread to other parts of the body by invading other tissues, shedding cancer cells into the abdomen or spreading to other organs.
- Invading – When a malignant stomach tumor grows it can invade organs adjacent to the stomach.
- Shedding – Cancer cells can break off (shed) from the original stomach tumor. New tumors may then form on the surface of nearby organs and tissues as the cells shed into the abdomen.
- Spreading – When cancer cells break away from the original tumor they can spread to other organs in the body through the blood vessels. These cancer cells can also spread through lymph vessels to nearby lymph nodes. The cells may attach to other tissues and grow to form new tumors that could damage the tissues they attached to.
The causes of stomach cancer are still largely unknown. However, it has been found that individuals predisposed to certain factors, will more likely develop stomach cancer than those without them.
Most people who have the increased risk factors do not develop stomach cancer. However, there are some patients who develop stomach cancer without having any of the increased risks.
The following are potential risk factors, some of which can be controlled, that may contribute to the potential development of stomach cancer:
- Long-term inflammation of the stomach – Conditions associated with long-term inflammation of the stomach increases the risk of stomach cancer. Pernicious anemia is a blood disease that can contribute to stomach inflammation. Long-term stomach inflammation can also result from having had part of the stomach removed. Over a period of years the risk for stomach cancer can increase after the removal because the patient may experience long-term stomach inflammation.
- Helicobacter Pylori Infection – A bacterium known as H. Pylori commonly affects the mucosa (inner lining) of the stomach and appears to be a major cause of stomach cancer. This can lead to inflammation of the stomach and peptic ulcers. This bacteria is also linked to some types of stomach lymphoma. However, few people affected with the bacteria do develop stomach cancer. Simple treatment can include antibiotic therapy and blood test or endoscopy to confirm successful treatment.
- Some Types of Stomach Polyps – Polyps are small mushroom like growths on the lining of the stomach. Most polyps do not increase the risk of stomach cancer. Adenomatous polyps or adenomas can sometimes develop into stomach cancer.
- Family History – If there is a history of several close relatives having stomach cancer then the risk of developing the disease can increase for other family members.
- Smoking – Smokers, especially heavy smokers, are more apt to develop stomach cancer than non-smokers and are at a higher risk of developing other cancers as well.
- Alcohol – Alcohol consumption increases the risk of developing stomach cancer in addition to other cancers.
- Obesity – Obesity presents a risk of cancer developing in the upper part of the stomach.
- Poor Diet – A diet high in smoked foods, salted fish and meat and pickled vegetables increases the risk for stomach cancer. A diet high in fresh vegetables and fruits may decrease the risk for stomach cancer.
- Lack of Physical Activity – This can become a cause for an increased risk in developing stomach cancer.
- Male Predominance – There is a higher incidence in male patients with a ration of one to three compared to female patients.
- Ethnicity – Stomach cancer is more common in the United States in Hispanic Americans and African Americans than in non-Hispanic Whites.
- Advanced Age – Patients have an average age of 70 for men 74 for women at the time of diagnosis.
- Prior stomach surgery – Patients who have had part of their stomach removed to treat other problems like ulcers seem more susceptible to developing stomach cancer.
- Menetrier Disease – This is a rare disease that includes changes in the stomach lining and may be considered as a risk of stomach cancer.
- Type A Bloo – People with type A blood have a higher risk of developing stomach cancer. The reason is unknown.
- Epstein-Barr Virus – This virus has been found in the stomach cancers of some patients. It is a virus that causes infectious mononucleosis. It hasn’t been confirmed that it is a cause of stomach cancer, but its presence has been found on occasions when the cancer exists.
- Workers in Certain Industries – People working in coal mining, nickel refining, rubber and timber processing industries are at a higher risk.
- Asbestos – Workers exposed to asbestos fibers are at a higher risk.
Stomach cancer usually does not display any symptoms in its early stages. As the cancer grows symptoms begin to develop. By the time the symptoms have developed, the cancer is usually in an advanced stage. However, symptoms from stomach cancer are very often indicative of other health issues unrelated to stomach cancer. Your doctor should be advised of these symptoms when they are present. If there is stomach cancer, it will be more susceptible to being treated successfully. The symptoms at different stages of the cancer include:
Early Stage Symptoms
- Indigestion or a burning sensation (heartburn)
- Appetite loss
- Pain or discomfort in the area of the abdomen
Middle Stage Symptoms
- Feeling bloated or full after having a small meal
- Weakness and fatigue
Late Stage Symptoms
- Difficulty swallowing
- Weight loss
- Nausea and vomiting
- Vomiting blood
- Blood in the stool
- Pain in the upper abdomen
- Diarrhea or constipation
Tests & Diagnosis
In addition to discussing your family history and ordering some blood or lab tests, the following tests may be ordered to determine the presence of stomach cancer:
- Physical Examination – The abdomen is felt to check for changes in the area as well as for fluid and swelling. The examination of lymph for swelling is also performed. Abdominal lumps can be found during a rectal examination.
- Upper GI Series – This test requires the patient to drink a barium solution and then x-rays are taken of the stomach, esophagus, and the first part of the intestine. The barium outlines the stomach in the x-ray. This enables the doctor to find tumors or other abnormal areas with the use of special imaging equipment.
- Endoscopy – An endoscope (thin lighted tube) is passed through the mouth and esophagus into the stomach. This enables the doctor to view the stomach. Prior to the procedure the throat is numbed with an anesthetic spray and drugs are used to sedate the patient.
- Biopsy – A biopsy is the only way to detect the presence of cancer cells with certainty. The endoscope has a tool for removing tissue from the stomach for a biopsy. The endoscopic procedure is described above. The tissue samples are studied by a pathologist under a microscope to determine the presence of cancer cells.
Unless stomach cancer is diagnosed at an early stage, before it has spread, it is difficult to cure. The difficulty with finding it at the early stage, is that early stomach cancer has few symptoms. When the disease is diagnosed it is most often in an advanced stage. Advanced stomach cancer can be treated and the symptoms can be relieved.
Several factors determine the treatment that will be selected to manage the stomach cancer. They include the stage of the cancer, as well as the size and location of the tumor. The patient’s age, overall health and personal preferences are also considered when developing a treatment plan. The primary goal is to eliminate the cancer when possible. If that is not an option then the goal is to prevent the cancer from growing and spreading. When treatments aren’t an option because the cancer is advanced and the treatments will not offer any benefits, other means may then be suggested to relieve the symptoms and help make the patient as comfortable as possible.
The location, type and stage of the cancer are the determining factors for the type of surgery that will be required. The entire stomach may be removed or just the part that is affected by the cancer. The goal of surgery is to remove all of the stomach cancer and a portion of healthy tissue. There are risks associated with including the risk of infection and bleeding. Digestive problems may arise when all or part of the stomach is removed. The surgical options available include:
- Removing early stage tumors from the stomach lining – If the cancers are very small and limited to the inside lining of the stomach, they may be removed with the use of an endoscope in a procedure known as endoscopic mucosal resection. The endoscope, a lighted tube with a camera, is passed down the throat into the stomach. Special instruments are used to remove the cancer and a portion of healthy tissue from the stomach lining.
- Partial (Subtotal) gastrectomy – This procedure is performed when tumors are located at the lower part of the stomach close to the intestines. The part of the stomach with the cancer is removed. There are times when part of the esophagus and the first part of the small intestine is also removed. The remaining part of the stomach is attached to the intestine. Lymph nodes and tissue located nearby may also be removed.
- Total gastrectomy – This procedure is performed for tumors located at the upper part of the stomach, or if the cancer has spread throughout the stomach. The complete stomach, parts of the esophagus and small intestine, lymph nodes and other tissues near the tumor are all removed. A portion of the pancreas may also have to be removed. There are rare instances when the spleen also has to be removed. The remaining part of the esophagus is then directly attached to the small intestine. Removing lymph nodes in the search for cancer – The surgeon may remove lymph nodes when partial or total gastrectomies are performed to make sure the cancer has not spread.
- Surgery to relieve symptoms and signs of stomach cancer – In cases where surgery is unable to cure the cancer, it can serve as a means to make the patient more comfortable. When part of the stomach is removed in people with advanced stomach cancer, the surgery may relieve the symptoms and discomfort associated with the growing tumor. This is known as palliative surgery.
- Cancer that blocks the digestive tract – When stomach cancer is in an advanced stage, a tumor may form that will block the passage of food through the digestive tract. This is treatable with:
- Radiation – This can possibly help shrink the tumor that is creating the blockage to the intestine.
- Stent – An endoscope is used to place a stent in the intestine. The stent is a tube made of metal mesh or plastic. Food and liquid can pass through the center of
the tube and essentially bypass the tumor.
- Laser – An endoscope is used to place a laser in the digestive tract. The laser is a concentrated beam of intense light that generates heat and kills tissue with
the heat. The cancer cells blocking the digestive tract are destroyed with the laser, and the obstruction is relieved.
The hospital stay for these procedures may extend to a week or more. The healing process is different for each individual. Medicine will help control the pain that may be experienced the first few days after the surgery. Aplan for the relief of pain is discussed prior to the surgery and it can be adjusted as needed. The patient may feel tired and weak for a period after the surgery and will have to be monitored for indications of infection, bleeding or other issues that will require some form of treatment.
Chemotherapy is given to most patients who have stomach cancer. Unfortunately, stomach cancer has not been particularly sensitive to chemotherapy. But the treatment usually does reduce
the size of the tumor, relieve symptoms and increase survival time. Chemotherapy is usually given in an outpatient setting at the hospital or doctor’s office. However, some people do have to stay in the hospital while receiving the treatment.
Chemotherapy is a treatment where medications are used to attack and kill cancer cells. These drugs travel in the blood stream throughout the body and kill cancer cells that may have gone beyond the stomach. A combination of medications is calculated by an oncologist based on staging and a patient’s overall health. The chemotherapy is usually administered intravenously and given at specific time intervals, determined by the oncologist, who works with the surgeon on the overall treatment plan for the patient.
Chemotherapy may be used before surgery to shrink the tumor so that it becomes easier to remove surgically. It can also be used after surgery to kill any cancer cells that may have remained in the body.
Radiation treatments are often used in combination with surgery and chemotherapy. When stomach cancer cannot be treated surgically, radiation is often used in combination with
chemotherapy to treat the cancer. It is sometimes used alone to help relieve symptoms in people with advanced stomach cancer, such as swelling and obstruction.
High-energy beams are used to kill cancer cells, shrink them, or damage them and keep them from growing. The radiation comes from a machine that aims radiation beams at the cancer in the abdomen. It affects only those cells in the part of the body that is being treated. Radiation can kill very small areas of cancer that cannot be seen and removed during surgery. It is generally given in a hospital or clinic five days a week, for several weeks.
Radiation may be used before surgery to shrink the tumor so that it becomes easier to remove surgically. It can also be used after surgery to kill any cancer cells that may have remained in the stomach area.
Radiation treatments are often used in combination with surgery and chemotherapy. When combined with chemotherapy after surgery, radiation can often delay or prevent recurrence of the
cancer. It may also help prolong the life of the patient. When stomach cancer cannot be treated surgically, radiation is often used in combination with chemotherapy to treat the cancer. It is used to relieve the pain, bleeding and eating problems by shrinking the tumor.
Medications used to attack specific abnormalities within cancer cells are considered targeted therapy. Trastuzumab (Herceptin®) is a man made version of an immune system protein. It is know as a monoclonal antibody and is used more often to treat breast cancer. Recent studies show that when given with chemotherapy it helped some patients with metastatic stomach cancer live longer compared to cases where chemotherapy was given alone. This drug is only helpful for the stomach cancers that contain a certain type of protein. The FDA has now approved it as part of the treatment for stomach cancer. There are drugs that are used to treat gastrointestinal stomach cancer which is a rare form of cancer. Imatinib (Gleevec)
and sunitinib (Sutent) are two such medications.
Food intake is an essential ingredient in the treatment of stomach cancer. Proper nutrition is fundamental to maintaining strength and healing. Having stomach cancer may make it difficult to eat. With the aid of the medical team and a nutritionist, a diet plan will help meet the needs of the patient. It is important to ingest the necessary amount of vitamins, proteins, calories and minerals the patient. This will help the patient prevent weight loss and discomfort when eating. There are cases where the intake of the required nutrition is assisted with the help of an IV (intravenous). Daily supplements of vitamins and minerals may be necessary after surgery. These include calcium, iron, vitamin D and vitamin D shots.
Studies used to test new forms of treatments are called clinical trials. They may include new surgical approaches, new approaches to radiation, testing new chemotherapy drugs, or even new methods such as gene therapy. These studies can lead to new methods becoming part of the standard treatment for the cancer when their results indicate safety and effectiveness.
Clinical trials offer access to treatments that aren’t ordinarily available. While they may produce serious unexpected side effects, they may provide positive results that would not have been received with the normally approved standard treatments. Clinical trials are closely monitored by the federal government to ensure safety for the patients participating in
While there are no specific known reasons for the cause of stomach cancer, there are known risks for it. The risks can be reduced by some lifestyle changes that include:
- Reduce the amount of salty and smoked foods that are eaten.
- Eat a substantial amount of fruits and vegetables.
- Don’t smoke.
- Weight control.
- Consult your doctor about your risks of getting stomach cancer – Some medical conditions as we stated in the risk section, do increase the risk for stomach cancer. If you get diagnosed with any of those conditions, you should discuss the method of closely monitoring those conditions with your doctor. This may include periodic endoscopies. The benefits of undergoing periodic testing may far outweigh the risks of not doing so.
- Surgery – Hereditary diffuse gastric cancer syndrome is a cause for a small percentage of stomach cancers. People who have that gene may decide to remove the stomach before the cancer develops. Most people with the gene do eventually develop stomach cancer. If there is a strong history of stomach cancer in the family surgery should be discussed with the doctor. Genetic counseling and testing can determine the presence of the gene.
The onset of stomach cancer can change a patient’s life and as well of the lives of their family and friends. Needing help after receiving this diagnosis is not uncommon, and there are many sources of support that help patients deal with all of the emotions and concerns that the diagnosis brings. Supportive care is available, before, during and after the treatment begins. Support groups offer support in person, over the telephone, or on the internet. In these groups patients and/or the family members will meet or talk to other patients and their family members who will share their experiences and acquired knowledge about how to deal with the disease and the effects of the treatments.
Doctors, nurses and other members of your health care team are also available to provide support and help deal with the emotions, concerns and physical issues associated with the diagnosis of stomach cancer.