Stomach cancer, or gastric cancer, is a buildup of abnormal cells that form a mass in part of the stomach. It can develop in any part of the stomach.

According to the World Health Organization (WHO), stomach cancer caused 783,000 deaths worldwide in 2018. It is the sixth most common cancer worldwide, but the third leading cause of cancer-related deaths.

In the United States, the number of new stomach cancer diagnoses has reduced by around 1.5% annually for the past decade.

Around 90–95% of all stomach cancers are adenocarcinomas. In this type, the cancer develops from the cells that form in the mucosa. This the lining of the stomach that produces mucus.

In this article, we look at how to recognize, diagnose, and treat stomach cancer, as well as the risk factors.

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Stomach cancer is the sixth most common cancer worldwide.

Stomach cancer can cause several symptoms. However, these symptoms may not appear for many years as stomach cancers grow very slowly.

For this reason, many people with stomach cancer do not receive a diagnosis until the disease is already advanced.

Early stage symptoms of stomach cancer include:

  • a sensation of being very full during meals
  • swallowing difficulties
  • feeling bloated after meals
  • frequent burping
  • heartburn
  • indigestion that does not resolve
  • stomach ache
  • pain in the breastbone
  • trapped wind
  • vomiting, which may contain blood

However, many of these symptoms are very similar to those of other, less serious conditions. However, anyone with an increased risk for stomach cancer who experiences swallowing difficulties should seek prompt medical treatment.

As the stomach cancer becomes more advanced, some people might experience the following symptoms:

  • anemia
  • a buildup of fluid in the stomach, which may cause the stomach to feel lumpy to the touch
  • black stools that contain blood
  • fatigue
  • loss of appetite
  • weight loss

Treatment for stomach cancer depends on several factors, including the severity of the cancer and the individual's overall health and preferences.

Treatments may include surgery, chemotherapy, radiation therapy, medications, and taking part in clinical trials.

Surgery

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There are surgical procedures available to treat stomach cancer.

A surgeon may try to remove the stomach cancer as well as a margin of healthy tissue. The surgeon needs to do this to ensure that they do not leave any cancerous cells behind.

Examples include:

  • Endoscopic mucosal resection: The surgeon will use endoscopy to remove tiny tumors from the mucosal layer. Doctors usually recommend this type of treatment for early stage stomach cancer that has not yet spread to other tissues.
  • Subtotal gastrectomy: This involves removing part of the stomach.
  • Total gastrectomy: A surgeon removes the whole stomach.

Abdominal surgeries are significant procedures and may require a long recovery period. People may have to stay in the hospital for 2 weeks after the procedure. Several weeks of recovery at home will follow this.

Radiation therapy

In radiation therapy, a specialist uses radioactive rays to target and kill cancerous cells. This type of therapy is not common in stomach cancer treatment because of the risk of harming nearby organs.

However, if the cancer is advanced or causing severe symptoms, such as bleeding or intense pain, radiation therapy is an option.

A healthcare team may combine radiation therapy with chemotherapy before surgery to shrink the tumors. This allows for easier surgical removal. They may also use radiation after surgery to kill any remaining cancer cells around the stomach.

People may experience indigestion, nausea, vomiting, and diarrhea as a result of undergoing radiation therapy.

Chemotherapy

Chemotherapy is a specialist treatment that uses drugs to stop rapidly-growing cancer cells from dividing and multiplying. These drugs are known as cytotoxic medicines. It is a primary treatment for stomach cancer that has spread to distant sites in the body.

The medication travels throughout the person's body and attacks cancer cells at the primary site of the cancer and any other regions to which it has spread.

In stomach cancer treatment, a cancer care team may administer chemotherapy to shrink the tumor before surgery or kill remaining cancer cells after surgery.

Targeted medications

Targeted therapies recognize and attack specific proteins that cancer cells produce. While chemotherapy targets rapidly dividing cells in general, targeted medications home in on cancer cells with other characteristics.

This reduces the number of healthy cells that chemotherapy destroys.

Cancer care teams administer two targeted medications for people with stomach cancer through an intravenous infusion (IV):

  • Trastuzumab (Herceptin): This targets HER2, a protein that promotes cell growth. Some stomach cancers produce an excess of HER2.
  • Ramucirumab (Cyramza): This medication focuses on blocking a protein called VEGF that tells the body to produce the new blood vessels that tumors need to grow.

Immunotherapy

This is a treatment that uses medicines to encourage the body's immune cells to attack cancer cells.

People with advanced stomach cancer who have received two or more other treatments are candidates for immunotherapy.

Individuals with persistent symptoms of stomach cancer should see their doctor as soon as possible.

The doctor will ask about their symptoms, family history, and medical history, as well as lifestyle choices, such as what they eat and drink and whether they smoke. They will also carry out a physical examination to check for stomach tenderness or lumpiness.

They may also perform blood tests to identify whether there is an excess of certain substances that indicate cancer. They may also perform a complete blood count to measure the number of red and white blood cells, as well as platelets and hemoglobin.

If the doctor suspects stomach cancer, they will refer the individual to a specialist in stomach diseases for tests. This specialist is known as a gastroenterologist.

Diagnostic measures may include the following.

Upper endoscopy

The specialist uses an endoscope to look inside the stomach. They examine the esophagus, stomach, and the duodenum, which is the first section of the small intestine.

If the doctor suspects cancer, they will do a biopsy to collect tissue samples, which they will send to a laboratory for analysis.

CT scan

A CT scan produces detailed, multi-angle images of regions inside the body.

Before a CT scan, a doctor might inject a dye or ask that the individual swallows it. This dye allows the scanner to produce clearer images of the affected areas.

Barium swallow

The individual swallows a liquid which contains barium that lines the esophagus and stomach. This helps identify anomalies in the stomach during an X-ray.

A radiologist will then take X-rays of the esophagus and stomach.

Certain factors increase the risk of cancer, including:

Medical conditions

Conditions linked to stomach cancer include:

  • H. pylori infection in the stomach
  • intestinal metaplasia, in which cells that would usually line the intestine line the stomach lining
  • peptic stomach ulcers
  • chronic atrophic gastritis, or long term stomach inflammation that makes the stomach lining thinner
  • pernicious anemia, which might develop due to a deficiency of vitamin B12
  • stomach polyps

Certain genetic conditions add to the risk of stomach cancer, including:

  • Li-Fraumeni syndrome
  • familial adenomatous polyposis (FAP)
  • Lynch syndrome
  • type A blood

Smoking

Regular, long-term smokers have an increased risk of stomach cancer when compared to non-smokers.

Read more on how to quit smoking.

Family history

Having a close relative who has or has had stomach cancer can increase the risk.

Diet

People who regularly eat salted, pickled, or smoked foods have a higher risk of developing gastric cancer. A high intake of red meat and refined grains also increases the risk of stomach cancer.

Some foods contain substances that may have links to cancer. For example, crude vegetable oils, cocoa beans, tree nuts, groundnuts, figs, and other dried foods and spices contain aflatoxins. Some studies have linked aflatoxins to cancer in some animals.

Age

The risk of developing stomach cancer increases significantly after the age of 50 years. According to the American Cancer Society, 60% of people who receive a stomach cancer diagnosis are at least 65 years old.

Sex

Men are more likely to get stomach cancer than women.

Some surgical procedures

Surgery to the stomach or a part of the body that affects the stomach, such as ulcer treatment, can increase the risk of stomach cancer years later.

People who experience symptoms and have one or more of these risk factors should see their doctor for a consultation.

There is no way to prevent stomach cancer entirely.

However, a person can take steps to reduce the risk of developing the disease. These include the following.

Diet

Several dietary measures can help reduce the risk of stomach cancer.

The American Cancer Society suggest that eating at least two and a half cups of fruits and vegetables every day can help limit the risk.

They also recommend reducing the quantity of pickled, salted, and smoked foods in the diet. Switching out refined grains for whole grain cereals, bread, and pasta and replacing red or processed meats with beans, fish, and poultry can also reduce a person's chance of developing stomach cancer.

Smoking

Smoking tobacco may increase the risk of cancer developing in the part of the stomach near the esophagus.

Those who smoke should seek advice on quitting. People who do not already smoke should avoid exposure to tobacco smoke.

Taking non-steroidal anti-inflammatory drugs (NSAIDS)

Using NSAIDs, such as aspirin, naproxen, or ibuprofen, may reduce the risk of stomach cancer. However, they carry additional risks, such as life threatening internal bleeding.

Only take NSAIDs to treat other conditions, such as arthritis. Do not take them solely to reduce the risk of stomach cancer.

Testing for other conditions and cancers

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People with a family history of stomach cancer may benefit from genetic testing.

Individuals who have hereditary diffuse gastric cancer syndrome and Lynch syndrome have a drastically increased risk of stomach cancer. Recognizing these and taking precautions after receiving a doctor's advice can reduce the risk.

People with close family members who have had stomach cancer and those who had invasive lobular breast cancer before the age of 50 years might benefit from genetic testing.

If a test shows changes in the CDH1 gene, a doctor may recommend removing the stomach before cancer develops.

Current research is looking into the possible cancer links of chronic Helicobacter pylori (H. pylori) infection in the stomach lining.

Early studies suggest that treating H. pylori infection with antibiotics can reduce the risk of stomach cancer, although further research is necessary.

The outlook after receiving a stomach cancer diagnosis is generally poor.

The relative 5-year survival rate is the likelihood that a person with stomach cancer will survive for 5 years or longer when compared to a person who does not have cancer. This reduces as the cancer becomes more aggressive and spreads beyond the original tumor.

If a person receives diagnosis and treatment before stomach cancer spreads, the 5-year survival rate is 68%. If the cancer metastasizes into deeper tissues in the stomach, this reduces to 31%.

Once the stomach cancer reaches distant organs, the survival rate drops to 5%.

Early diagnosis is key to improving the outlook for stomach cancer.