Metastatic stomach cancer is cancer that has spread beyond your stomach to distant tissues. Treatment generally focuses on extending your life and reducing symptoms.

Metastatic stomach cancer is also called stage 4 stomach cancer. It’s the most advanced form of the disease and the most difficult to treat.

Stomach cancer can spread to many different areas in your body through your bloodstream and lymph system. It most commonly spreads to your:

  • liver
  • peritoneum
  • lungs

Read on to learn more about metastatic stomach cancer, including symptoms, treatment options, and outlook.

What are the different stages of cancer?

Cancer staging is part of the diagnosis process. It gives you an overview of what to expect and helps determine the best treatment options.

Learn more about the stages of cancer here.

Metastatic stomach cancer is a type of cancer that spreads from your stomach to distant tissues in your body. The process of spreading to distant areas is called metastasizing, and the new cancer locations are called metastases.

Stomach cancer occurred at a rate of 7.0 people per 100,000 people per year in the United States from 2017 to 2021, according to the National Cancer Institute’s SEER program. Of these cancers, 33.7% of newly diagnosed stomach cancers were metastatic cancers.

Stomach cancer can often grow for many years before causing symptoms. Research suggests that the time it takes for early cancer to double in size is often between 577 to 3,462 days. Many factors can influence how quickly your cancer grows, such as your type and subtype of cancer.

Diffuse stomach cancer tends to be an aggressive form of the disease and can spread to distant tissues easily. Diffuse cancers occur widely throughout your stomach as opposed to a solitary tumor.

Stomach cancer risk factors

Stomach cancer risk factors include:

  • male biological sex
  • increasing age
  • Helicobacter pylori infection
  • having overweight or obesity
  • diet high in salt or processed meats
  • eating few fruits
  • alcohol use (if it is over 3 drinks per day)
  • tobacco use
  • previous stomach surgery
  • some types of stomach polyps
  • pernicious anemia
  • Menetrier disease
  • family history
  • Epstein-Barr infection
  • “A” blood type
  • people who work in coal, metal, or rubber industries
  • in the United States, the following ancestries
    • African
    • Hispanic
    • Native American
    • Asian American
    • Pacific Islander

General symptoms of stomach cancer include:

Other symptoms of metastatic stomach cancer can depend on which part of your body the cancer spreads to.

Liver metastases

Symptoms that stomach cancer has spread to your liver include:

Lymph node spread

Signs that stomach cancer has spread to lymph nodes include:

Peritoneum metastases

The peritoneum is a membrane that lines your abdominal cavity. Signs and symptoms that stomach cancer has spread to your peritoneum include:

Lung metastases

Signs and symptoms that stomach cancer has spread to your lungs include:

  • a cough that doesn’t go away
  • breathlessness
  • ongoing chest infections
  • fluid buildup in your lungs

It’s not particularly common for other cancers to metastasize to your stomach. They more commonly travel to areas such as your brain, lungs, or liver.

Some of the most common cancers that metastasize to your stomach include:

Initial tests your doctor will perform to diagnose stomach cancer include:

  • review of your personal and family medical history
  • physical exam
  • review of your symptoms

If they suspect stomach cancer, you may receive additional tests such as:

  • endoscopy, a long tube with a camera that’s inserted down your throat
  • a biopsy of your stomach tissue
  • blood tests
  • ultrasound
  • other imaging test such as:

Doctors generally do not consider metastatic stomach cancer to be curable, so treatment is usually palliative, meaning it aims to reduce your symptoms and prolong your life.

Treatments depend on whether your cancer has a particular gene mutation called HER2. Cancers with this mutation are called HER2-positive, and cancers without it are called HER2-negative.

Initial treatment for HER2-negative cancer is usually chemotherapy with or without the immunotherapy drug nivolumab (Opdivo).

The initial treatment for HER2-positive cancer is often the immunotherapy drug pembrolizumab (Keytruda) with the targeted therapy drug trastuzumab (Herceptin) and chemotherapy.

Doctors often use 5-year relative survival rate to measure how likely you are to survive a particular cancer. This metric measures how many people with cancer are alive 5 years later compared to people without that cancer.

The 5-year relative survival rate for all stomach cancers in the United States from 2013 to 2019 was 36%. The 5-year relative survival rate for cancers that spread to distant body parts was 7%.

Metastatic stomach cancer has spread to other organs beyond your stomach. It tends to have a less favorable survival rate, and treatment focuses on prolonging your survival and improving your quality of life.

The initial treatment for metastatic cancer depends on whether your cancer has a particular gene mutation called HER2. It often consists of some combination of immunotherapy, chemotherapy, and targeted therapy.