When a doctor suspects a person has stomach cancer, they will refer them to a specialist for tests. If the person receives a diagnosis, a doctor may refer them for further testing to determine the best course of treatment.

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Medical professionals use many tests to detect or diagnose stomach cancer. Once a person receives a diagnosis, a doctor may refer them for additional tests to learn if their cancer has spread to other parts of the body and determine the best course of treatment.

According to the American Cancer Society (ACS), a biopsy is the only way to accurately diagnose stomach cancer. A 2019 study also suggests that multiple biopsies may increase diagnostic accuracy.

This article explains the types of tests that can help a doctor diagnose stomach cancer.

A physical exam is often one of the first exams a medical professional performs when trying to diagnose an ailment. For example, if a person complains of abdominal bloating, a doctor may feel the abdomen for lumps or tenderness.

A doctor will also ask a person about their medical history during a physical exam. They may ask about symptoms the person is experiencing, such as difficulty with eating or digestion.

A doctor may order blood tests that check for anemia, potentially resulting from internal bleeding in the stomach.

If a doctor suspects a problem with the stomach or other parts of the gastrointestinal tract, they will likely refer the person to a gastroenterologist for further testing.

If a doctor suspects a person has stomach cancer, an upper endoscopy is one of the first tests they will perform. It involves inserting a thin, lighted tube through a person’s mouth to look for abnormal areas in the esophagus, stomach, and the first part of the small intestine.

If they detect abnormal areas, they take a tissue biopsy for further testing.

A 2021 Norweigian population-based study shows that doctors do not always detect stomach cancer using upper endoscopy. Of 730 people with gastric cancer, doctors failed to detect cancer 9.2% of the time. Researchers suggest that follow-up appointments and robust biopsy sampling of people with gastric ulcerations could reduce the rate of missed gastric cancers.

In some people, an endoscopy may help eliminate very early-stage stomach cancer. Endoscopy may also prevent or relieve symptoms and other complications from the disease without invasive surgery.

The only way to diagnose stomach cancer is by performing a biopsy. Doctors often biopsy tissue during an upper endoscopy. If the doctor identifies any abnormal areas in the stomach lining during the examination, they will pass an instrument down the endoscope to get a biopsy sample.

A pathologist then evaluates the tissue sample in a laboratory to diagnose the disease.

An abnormal result could indicate that a person has stomach cancer or another condition, such as a bacterial infection or inflammation.

The following imaging tests may also help diagnose stomach cancer:

Doctors may recommend these tests to look for suspected tumors and other abnormalities in a person’s stomach and esophagus.

The following tests can help a doctor confirm the stage of cancer and determine an appropriate course of treatment:

  • laparoscopy
  • liver function test
  • kidney function test
  • blood tests
  • electrocardiogram (EKG) or echocardiogram

Below, we answer some common questions about stomach cancer tests.

Does stomach cancer show up in blood tests?

Blood tests cannot diagnose stomach cancer, but they can provide clues about a person’s health and help a doctor make a diagnosis. A doctor might order blood tests to look for anemia, which might result from cancer bleeding into the stomach.

Can doctors detect stomach cancer early?

Cancer screening involves looking for cancer before a person has any symptoms. Stomach cancer accounts for only 1.5% of all new cancers diagnosed in the United States. And according to the ACS, there are no routine screening recommendations for stomach cancer.

Most people receive a diagnosis when they start to experience symptoms of the disease. However, symptoms tend to show up only once the cancer progresses.

Diagnosing stomach cancer involves different types of tests. The tools a doctor uses to diagnose stomach cancer depend on a person’s symptoms, medical history, and previous test results.

Stomach cancers can grow very slowly, meaning a person may not have symptoms for many years. Additionally, many people with stomach cancer do not receive a diagnosis until the disease has already advanced.

While there is currently no screening recommendation, stomach cancer screening is an active area of cancer research. Scientists are studying other ways to detect stomach cancer before it causes symptoms to improve outcomes.