Stomach cancer

Most of us know what stomach is, but for those of us who doesn't know, the stomach is a J-shaped organ in the upper abdomen. Stomach is the part of gastrointestinal systems that stores and digests food. It processes nutrients (vitamins, minerals, carbohydrates, fats, proteins, and water) in foods that are eaten and helps pass waste material out of the body. Esophagus connects back part of the mouth to the stomach. Esophagus is a hollow, muscular tube. Partly digested food form the stomach passes into the small intestine and then into the large intestine.

In medicine, stomach cancer (also called gastric cancer) can develop in any part of the stomach and may spread throughout the stomach and to other organs. The cancer 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.

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 and the disease is metastatic stomach cancer, not liver cancer.

A well known complication of stomach cancer is when it spreads to an ovary; the tumor in the ovary is called a Krukenberg tumor This tumor, named for the doctor who first described it, 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.

Epidemiology

Stomach cancer is more prevalent in China, Japan, Korea, and other countries in Asia and South America, than in the United States.

Symptoms

Stomach cancer can be hard to find early. Often there are no symptoms in the early stages and, in a number of 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 abdominal pain;
• 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
• Upper GI series
• Gastroscopic exam

Abnormal tissue seen in a gastroscope examination will be biopsied by the surgeon or gastroenterologist. This tissue is then sent to a pathologist for histological examination under a microscope to check for the presence of malignant cells. A biopsy, with subsequent histological analysis, is the only sure way to confirm the presence of cancer cells.

Histopathology

• Gastric adenocarcinoma is a cancerous epithelial tumor, originating from glandular epithelium of the gastric mucosa. It invades the gastric wall, infiltrating the muscularis mucosae, the submucosa and thence the muscularis propria. Histologically, there are two major types of gastric cancer (Lauren classification): intestinal type and diffuse type.
• Intestinal type adenocarcinoma: tumor cells describe irregular tubular structures, harboring pluristratification, multiple lumens, reduced stroma ("back to back" aspect). Often, it associates intestinal metaplasia in neighboring mucosa. Depending on glandular architecture, cellular pleomorphism and mucosecretion, adenocarcinoma may present 3 degrees of differentiation: well, moderate and poorly differentiate.
• Diffuse type adenocarcinoma (mucinous, colloid): Tumor cells are discohesive and secrete mucus which is delivered in the interstitium producing large pools of mucus/colloid (optically "empty" spaces). It is poorly differentiated. If the mucus remains inside the tumor cell, it pushes the nucleus at the periphery - "signet-ring cell". [1]

Staging

If cancer cells are found in the tissue sample, the next step is to stage, or find out the extent of the disease. Various tests determine 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 Computerized axial tomography 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 therapy after surgery depend on these findings.

Treatment

Treatment is commonly adapted to fit each patient's individual needs and depends on the size, location, and extent of the tumor, the stage of the disease, the patient's general health and other factors.

A number of patients with cancer are motivated to learn all they can about the disease and their therapy 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 therapy 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 therapy choices, the patient may want to ask about taking part in a research study. Such studies, called clinical trials, are designed to improve cancer therapy.

Patients and their loved ones are naturally concerned about the effectiveness of the therapy. 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; therapys 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 a number of patients recover completely, doctors use this term because the disease can return. (The return of cancer is called a recurrence.)

Getting a second opinion

Treatment decisions are complex. Sometimes it is helpful for patients to have a second opinion about the diagnosis and the therapy plan. (Some insurance companies require a second opinion; others may pay for a second opinion if the patient requests it.) There are several ways to find another doctor to consult:

• The patient's doctor may be able to suggest a specialist. Specialists who treat this disease include gastroenterologists, surgeons, medical oncologists and radiation oncologists.
• The Cancer Information Service, at 1-800-4-CANCER, can tell callers about therapy facilities, including cancer centers and other programs supported by the National Cancer Institute.
• Patients can get the names of doctors from their local medical society, a nearby hospital, or a medical school.

Methods of therapy

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 commonly advanced when the diagnosis is made. However, advanced stomach cancer can still be treated and the symptoms can be relieved. Treatment for stomach cancer may include surgery, chemotherapy, and/or radiation treatment. New therapy approaches such as biological treatment and improved ways of using current methods are being studied in clinical trials. A patient may have one form of therapy or a combination of therapys.

Surgery is the most common therapy 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 therapy is called systemic treatment 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. Researchers are exploring the benefits of giving chemotherapy before surgery to shrink the tumor, or as adjuvant treatment after surgery to destroy remaining cancer cells. Combination therapy with chemotherapy and radiation treatment is also under study. Doctors are testing a therapy in which anticancer drugs are put directly into the abdomen (intraperitoneal chemotherapy). Chemotherapy also is being studied as a therapy 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 therapy period followed by a recovery period, then another therapy, and so on. Commonly 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 treatment (also called radiotherapy) is the use of high-energy rays to damage cancer cells and stop them from growing. Like surgery, it is local treatment; the radiation can affect cancer cells only in the treated area. Radiation treatment is sometimes given after surgery to destroy cancer cells that may remain in the area. Scientists are conducting clinical trials to find out whether it is helpful to give radiation treatment during surgery (intraoperative radiation treatment). Radiation treatment may also be used to relieve pain or blockage.

Clinical trials

A number of patients with stomach cancer are treated in clinical trials. 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 therapys that have shown promise in laboratory research. In clinical trials, some patients may receive the new therapy 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 therapy methods. Scientists also use clinical trials to look for ways to reduce the side effects of therapy and to improve the quality of patients' lives.

Side effects of therapy

It is hard to limit the effects of treatment so that only cancer cells are removed or destroyed. Because healthy cells and tissues also may be damaged, therapy can cause unpleasant side effects.

The side effects of cancer therapy are different for each person, and they may even be different from one therapy to the next. Doctors try to plan therapy 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 therapy.

Surgery

Gastrectomy is major surgery. For a period of time after the surgery, 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 the 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 commonly encouraged not to drink at mealtimes. Medicine also can help control the dumping syndrome. The symptoms commonly 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.

Chemotherapy

The side effects of chemotherapy depend mainly on the drugs the patient receives. As with any other type of therapy, 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, particularly with nausea and vomiting. These effects commonly go away gradually during the recovery period between therapys or after the therapys stop.

Radiation treatment

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 commonly best. It is important for patients to take good care of their skin during therapy, but they should not use lotions or creams without the doctor's advice.

Patients are likely to become very tired during radiation treatment, particularly in the later weeks of therapy. Resting is important, but doctors commonly advise patients to try to stay as active as they can.

Biological treatment

The side effects of biological treatment vary with the type of therapy. 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 therapy.

Nutrition for 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 food energy 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 therapy. Patients and their families also may want to read the National Cancer Institute booklet Eating Hints for Cancer Patients, which contains a number of useful suggestions.

External links

• Stomach cancer news