Stomach cancer is cancer that develops in cells of the stomach. Symptoms typically do not develop until the later stages of the disease.

In some cases, people with stomach cancer may have gastric symptoms, such as persistent indigestion, nausea, and abdominal pain or discomfort.

People may have more widespread symptoms during the later stages of stomach cancer, if the cancer spreads from the stomach to other parts of the body.

This article outlines some symptoms of stomach cancer a person may experience during the early and later stages of the disease.

The article also describes how stomach cancer typically starts, how long it can go undetected, and when to seek medical attention for stomach cancer symptoms.

According to the American Cancer Society, early stage stomach cancer rarely causes symptoms. Most people only become aware they have stomach cancer once the tumor has grown large or spread to areas outside of the stomach.

When stomach cancer symptoms do occur, they may be confined to the gastrointestinal (GI) tract. Examples include:

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

The above symptoms are usually due to conditions other than stomach cancer. However, it’s a good idea to have a medical checkup, particularly if symptoms persist or worsen.

In most cases, people with stomach cancer only develop symptoms during the later stages of the disease. They may develop new or worsening gastric symptoms. They may also experience more widespread symptoms, such as:

  • vomiting
  • difficulty swallowing
  • stomach pain
  • abdominal swelling
  • blood in the stool
  • unintentional weight loss
  • tiredness or weakness
  • yellowing of the skin and eyes, which may occur if the cancer spreads to the liver
  • swelling of the lymph nodes

According to the American Cancer Society, stomach cancers typically develop slowly over many years. In the earliest stages, precancerous changes occur in the stomach lining. These changes rarely cause symptoms.

Cancers can develop in different sections of the stomach. The American Cancer Society lists four main types of stomach cancer:

  • Adenocarcinomas: These cancers begin in gland cells in the innermost lining of the stomach. Adenocarcinomas account for around 90–95% of all stomach cancers. There are two types:
    • Intestinal adenocarcinoma: This type is the more common of the two. It features cancer cells that are more likely to respond to treatment with targeted drug therapy. Because of this, outcomes are more favorable.
    • Diffuse adenocarcinoma: This type is less common. It tends to grow and spread more quickly. Because of this, it’s more difficult to treat.
  • Gastrointestinal stromal tumors (GISTs): These tumors develop in cells called interstitial cells of Cajal (ICCs), which line the GI tract. Most GISTs develop in the stomach, though they can develop anywhere in the GI tract. There are different types of GIST. Some are more prone to spreading, or metastasizing.
  • Neuroendocrine tumors: These tumors develop in cells in the stomach or other parts of the GI tract. Most types are slow growing and do not spread to other organs. However, some are fast growing and spread quickly.
  • Lymphomas: These cancers begin in immune cells called lymphocytes. Some lymphomas start in the stomach wall, while others start elsewhere in the body.

Other rare cancers that may start in the stomach include:

  • squamous cell carcinomas
  • small cell carcinomas
  • leiomyosarcomas

The most common type of stomach cancer is intestinal adenocarcinoma. It tends to grow very slowly without causing any symptoms. As such, it may go undetected for years.

There’s no routine screening for stomach cancer among people who have an average risk of the disease. But a doctor may recommend routine screening if you have a higher risk of stomach cancer, such as if you:

Stomach cancer screening can help doctors detect and treat the disease earlier, improving your outlook.

Anyone who experiences gastric issues should contact a doctor for a diagnosis, particularly if their symptoms persist or worsen.

While most gastric symptoms are due to conditions other than stomach cancer, it’s important for a doctor to rule out stomach cancer and other serious causes.

Also visit a doctor if you experience more generalized symptoms, such as:

  • weakness and fatigue
  • unexplained weight loss
  • yellowing of the skin and eyes

Early detection and treatment of stomach cancer are associated with increased survival rates.

The table below shows the 5-year relative survival rates for different stages of stomach cancer at diagnosis, according to the National Cancer Institute:

Cancer stage at diagnosisDescription5-year relative survival rate
localizedcancer has not spread outside of the stomach75%
regional cancer has spread outside of the stomach to nearby lymph nodes or other nearby tissues35%
distantcancer has spread to distant organs, lymph nodes, or other distant tissues7%

A 5-year relative survival rate compares the likelihood that a person with a certain condition will survive for 5 years compared with people in the larger population.

The above data comes from diagnoses made 5 years ago. Cancer treatments are continually improving, and today’s figures may be higher than those presented here. This data also does not take into account your unique health factors and situation.

Stomach cancer does not usually cause symptoms in the early stages. If symptoms are present, they are likely confined to the gastric system and may worsen as the disease progresses.

In the later stages, a person may develop more widespread symptoms, such as weakness, fatigue, and jaundice.

Doctors do not advise routine screenings for stomach cancer among people with an average risk of the disease. However, doctors may recommend routine screenings for those at increased risk.

Since early stage stomach cancer rarely causes symptoms, screenings are the most reliable way to detect early stage disease.