stomach cancer

The stomach

The stomach is a hollow organ in the upper abdomen, under the ribs.

It's part of the digestive system. Food moves from the mouth through the esophagus to the stomach. In the stomach, the food becomes liquid. Muscles in the stomach wall push the liquid into the small intestine.

The wall of the stomach has five layers:

Inner layer or lining (mucosa): Juices made by glands in the inner layer help digest food. Most stomach cancers begin in this layer.
Submucosa: This is the support tissue for the inner layer.
Muscle layer: Muscles in this layer contract to mix and mash the food.
Subserosa: This is the support tissue for the outer layer.
Outer layer (serosa): The outer layer covers the stomach. It holds the stomach in place.

Understanding cancer

Cancer begins in cells, the building blocks that make up tissues. Tissues make up the organs of the body.

Normally, cells grow and divide to form new cells as the body needs them. When cells grow old, they die, and new cells take their place.

Sometimes, this process goes wrong. New cells form when the body does not need them, and old or damaged cells do not die as they should. The buildup of extra cells often forms a mass of tissue called a growth, polyp, or tumor.

Tumors in the stomach can be benign (not cancer) or malignant (cancer). Benign tumors are not as harmful as malignant tumors:

Benign tumors:
are rarely a threat to life
can be removed and usually don't grow back
don't invade the tissues around them
don't spread to other parts of the body
Malignant tumors:
may be a threat to life
often can be removed but sometimes grow back
can invade and damage nearby organs and tissues
can spread to other parts of the body

Stomach cancer usually begins in cells in the inner layer of the stomach. Over time, the cancer may invade more deeply into the stomach wall. A stomach tumor can grow through the stomach's outer layer into nearby organs, such as the liver, pancreas, esophagus, or intestine.

Stomach cancer cells can spread by breaking away from the original tumor. They enter blood vessels or lymph vessels, which branch into all the tissues of the body. The cancer cells may be found in lymph nodes near the stomach. The cancer cells may attach to other tissues and grow to form new tumors that may damage those tissues.

The spread of cancer is called metastasis. See the Staging section for information about stomach cancer that has spread.


note:Adenocarcinoma is the most common type of stomach cancer.


what are the risk factors and causes?

octors do know that people with certain risk factors are more likely than others to develop stomach cancer. A risk factor is something that may increase the chance of getting a disease.

Studies have found the following risk factors for stomach cancer:

Helicobacter pylori infection: H. pylori is a bacterium that commonly infects the inner lining (the mucosa) of the stomach. Infection with H. pylori can cause stomach inflammation and peptic ulcers. It also increases the risk of stomach cancer, but only a small number of infected people develop stomach cancer.
Long-term inflammation of the stomach: People who have conditions associated with long-term stomach inflammation (such as the blood disease pernicious anemia) are at increased risk of stomach cancer. Also, people who have had part of their stomach removed may have long-term stomach inflammation and increased risk of stomach cancer many years after their surgery.
Smoking: Smokers are more likely than nonsmokers to develop stomach cancer. Heavy smokers are most at risk.
Family history: Close relatives (parents, brothers, sisters, or children) of a person with a history of stomach cancer are somewhat more likely to develop the disease themselves. If many close relatives have a history of stomach cancer, the risk is even greater.
Poor diet, lack of physical activity, or obesity:
Studies suggest that people who eat a diet high in foods that are smoked, salted, or pickled have an increased risk for stomach cancer. On the other hand, people who eat a diet high in fresh fruits and vegetables may have a lower risk of this disease.
A lack of physical activity may increase the risk of stomach cancer.
Also, people who are obese may have an increased risk of cancer developing in the upper part of the stomach.

Most people who have known risk factors do not develop stomach cancer. For example, many people have an H. pylori infection but never develop cancer.

On the other hand, people who do develop the disease sometimes have no known risk factors.


Symptoms

Early stomach cancer often does not cause symptoms. As the cancer grows, the most common symptoms are:

Discomfort or pain in the stomach area
Difficulty swallowing
Nausea and vomiting
Weight loss
Feeling full or bloated after a small meal
Vomiting blood or having blood in the stool

Most often, these symptoms are not due to cancer. Other health problems, such as an ulcer or infection, can cause the same symptoms. Anyone who has these symptoms should tell their doctor so that problems can be diagnosed and treated as early as possible.

Diagnosis

If you have symptoms that suggest stomach cancer, your doctor will check to see whether they are due to cancer or to some other cause. Your doctor may refer you to a gastroenterologist, a doctor whose specialty is diagnosing and treating digestive problems.

Your doctor will ask about your personal and family health history. You may have blood or other lab tests. You also may have:

Physical exam: Your doctor feels your abdomen for fluid, swelling, or other changes. Your doctor also will check for swollen lymph nodes.
Endoscopy: Your doctor uses a thin, lighted tube (endoscope) to look into your stomach. Your doctor first numbs your throat with an anesthetic spray. You also may receive medicine to help you relax. The tube is passed through your mouth and esophagus to the stomach.
Biopsy: An endoscope has a tool for removing tissue. Your doctor uses the endoscope to remove tissue from the stomach. A pathologist checks the tissue under a microscope for cancer cells. A biopsy is the only sure way to know if cancer cells are present.

You may want to ask your doctor these questions before having a biopsy:

How will the biopsy be done?
Will it hurt?
Are there any risks? What are the chances of infection or bleeding after the biopsy?
When can I resume my normal diet?
How soon will I know the results?
If I do have cancer, who will talk to me about next steps? When?


Treatment

The choice of treatment depends mainly on the size and location of the tumor, the stage of disease, and your general health.

Treatment for stomach cancer may involve surgery, chemotherapy, or radiation therapy. You'll probably receive more than one type of treatment. For example, chemotherapy may be given before or after surgery. It's often given at the same time as radiation therapy.

You may want to talk with your doctor about taking part in a clinical trial, a research study of new treatment methods. Clinical trials are an important option for people at any stage of stomach cancer.

You may have a team of specialists to help plan your treatment. Your doctor may refer you to a specialist, or you may ask for a referral. Specialists who treat stomach cancer include gastroenterologists, surgeons, medical oncologists, and radiation oncologists. Your health care team may also include an oncology nurse and a registered dietitian.

Your health care team can describe your treatment choices, the expected results, and the possible side effects. Because cancer therapy often damages healthy cells and tissues, side effects are common. Before treatment starts, ask your health care team about possible side effects, how to prevent or reduce these effects, and how treatment may change your normal activities. You and your health care team can work together to make a treatment plan that meets your needs.

You may want to ask your doctor these questions before you begin treatment:

What is the stage of the disease? Has the cancer spread? Do any lymph nodes show signs of cancer?
What is the goal of treatment? What are my treatment choices? Which do you suggest for me? Why?
What are the expected benefits of each kind of treatment?
What can I do to prepare for treatment?
Will I need to stay in the hospital? If so, for how long?
What are the risks and possible side effects of each treatment? How can side effects be managed?
What is the treatment likely to cost? Will my insurance cover it?
How will treatment affect my normal activities? Am I likely to have eating or other problems?
Would a research study (clinical trial) be a good choice for me?
Can you recommend other doctors who could give me a second opinion about my treatment options?
How often should I have checkups?


staging (if its in syllabus then hai)

if the biopsy shows that you have stomach cancer, your doctor needs to learn the stage (extent) of the disease to help you choose the best treatment.

Staging is a careful attempt to find out the following:

How deeply the tumor invades the wall of the stomach
Whether the stomach tumor has invaded nearby tissues
Whether the cancer has spread and, if so, to what parts of the body.

When stomach cancer spreads, cancer cells may be found in nearby lymph nodes, the liver, the pancreas, esophagus, intestine, or other organs. Your doctor may order blood tests and other tests to check these areas:

Chest x-ray: An x-ray of your chest can show whether cancer has spread to the lungs.
CT scan: An x-ray machine linked to a computer takes a series of detailed pictures of your organs. You may receive an injection of dye. The dye makes abnormal areas easier to see. Tumors in your liver, pancreas, or elsewhere in the body can show up on a CT scan.
Endoscopic ultrasound: Your doctor passes a thin, lighted tube (endoscope) down your throat. A probe at the end of the tube sends out sound waves that you cannot hear. The waves bounce off tissues in your stomach and other organs. A computer creates a picture from the echoes. The picture can show how deeply the cancer has invaded the wall of the stomach. Your doctor may use a needle to take tissue samples of lymph nodes.
Laparoscopy: A surgeon makes small incisions (cuts) in your abdomen. The surgeon inserts a thin, lighted tube (laparoscope) into the abdomen. The surgeon may remove lymph nodes or take tissue samples for biopsy.

Sometimes staging is not complete until after surgery to remove the tumor and nearby lymph nodes.

When stomach cancer spreads from its original place to another part of the body, the new tumor has the same kind of abnormal cells and the same name as the primary (original) tumor. For example, if stomach cancer spreads to the liver, the cancer cells in the liver are actually stomach cancer cells. The disease is metastatic stomach cancer, not liver cancer. For that reason, it is treated as stomach cancer, not liver cancer. Doctors call the new tumor "distant" or metastatic disease.

These are the stages of stomach cancer:

Stage 0: The tumor is found only in the inner layer of the stomach. Stage 0 is also called carcinoma in situ.
Stage I is one of the following:
The tumor has invaded only the submucosa. Cancer cells may be found in up to 6 lymph nodes.
Or, the tumor has invaded the muscle layer or subserosa. Cancer cells have not spread to lymph nodes or other organs.
Stage II is one of the following:
The tumor has invaded only the submucosa. Cancer cells have spread to 7 to 15 lymph nodes.
Or, the tumor has invaded the muscle layer or subserosa. Cancer cells have spread to 1 to 6 lymph nodes.
Or, the tumor has penetrated the outer layer of the stomach. Cancer cells have not spread to lymph nodes or other organs.
Stage III is one of the following:
The tumor has invaded the muscle layer or subserosa. Cancer cells have spread to 7 to 15 lymph nodes.
Or, the tumor has penetrated the outer layer. Cancer cells have spread to 1 to 15 lymph nodes.
Or, the tumor has invaded nearby organs, such as the liver, colon, or spleen. Cancer cells have not spread to lymph nodes or to distant organs.
Stage IV is one of the following:
Cancer cells have spread to more than 15 lymph nodes.
Or, the tumor has invaded nearby organs and at least 1 lymph node.
Or, cancer cells have spread to distant organs.