Stomach cancer is cancer that begins in the stomach. In the early stages, stomach cancer may cause stomach discomfort, indigestion, and loss of appetite.

Stomach cancer does not always cause symptoms in the early stages. If symptoms do occur, they can include bloating, unexplained weight loss, and nausea.

Many other conditions can cause similar symptoms, but a person will need to contact a doctor if they have any persistent or unusual symptoms.

Doctors may use a range of tests, such as blood tests, an endoscopy, and imaging tests, to find out if a person has stomach cancer.

This article looks at stomach cancer, early detection, warning signs, diagnosis, and more.

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Symptoms of stomach cancer may include the following:

Doctors may recommend routine screening for people who have a high risk of stomach cancer, such as those with certain genetic disorders.

This may help them to detect stomach cancer early with tests such as an endoscopy.

In the United States, experts do not currently recommend routine screening for people with an average risk of stomach cancer.

To check if a person has stomach cancer, doctors may carry out the following:

  • a physical exam of the abdomen to check for any abnormal signs
  • a full medical history, including family history
  • blood chemistry tests to check for higher or lower levels of certain substances, which may indicate cancer
  • a complete blood count to check the quantity of red blood cells, as well as levels of white blood cells, platelets, and hemoglobin
  • an upper endoscopy, which uses a flexible tube with a camera to examine the inside of the esophagus, stomach, and first part of the small intestine
  • a biopsy, in which doctors may take a tissue sample during an endoscopy for laboratory testing
  • imaging scans, such as X-rays, CT scans, and PET scans

Tests such as upper endoscopy may help doctors to detect stomach cancer early. An endoscopy can help doctors identify small, subtle changes that may indicate cancer.

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Learn more about stomach cancer.

People should contact a doctor if they have any symptoms of stomach cancer, particularly if symptoms do not go away or worsen.

Many benign conditions, such as an infection or ulcer, may cause similar symptoms to stomach cancer.

It is important for a person to find out the underlying cause of any unusual or persistent symptoms.

People will need to see a doctor if they have any stomach cancer symptoms for more than two weeks. These include unexplained weight loss, severe abdominal pain, nausea and vomiting, and tarry or bloody stools.

This section answers some common questions about what it feels like to have stomach cancer.

What are the first warning signs of stomach cancer?

In the early stages, stomach cancer may not cause any symptoms. If a person does experience symptoms of early stage cancer, these may include:

  • stomach discomfort
  • indigestion
  • heartburn
  • feeling bloated after eating
  • mild nausea
  • loss of appetite

How do you feel when you have stomach cancer?

People may experience abdominal symptoms with stomach cancer, such as stomach pain or discomfort, and can feel full after eating only a little. They may also feel nauseous.

A person may feel more tired than usual with stomach cancer. People with stomach cancer may have anemia due to a low red blood cell count, which can cause fatigue, weakness, and shortness of breath.

Cancer causes changes in the body that can cause people to feel very tired, even after resting. The worry of cancer may also cause people to feel fatigued.

How do you check for stomach cancer?

It can be difficult to check for stomach cancer because, in the early stages of the disease, it may not cause any symptoms. Many symptoms of early stomach cancer can be similar to those of other gastrointestinal conditions.

There is no routine screening for stomach cancer for the general population, but people at high risk may have routine screening to check for stomach cancer.

Knowing the early signs and symptoms can help people be aware of anything unusual. They should see a doctor as soon as possible with any concerning symptoms.

Stomach cancer may not cause any symptoms in the early stages, but if people do have symptoms, they may experience abdominal pain and discomfort.

A person may feel full after eating a small amount, and they may have bloating, indigestion, or nausea. Fatigue and unexplained weight loss can also be signs of cancer.

Many other conditions can cause similar symptoms to stomach cancer, but it is important for a person to see a doctor to find out the underlying cause of any persistent or concerning symptoms.