With stomach cancer, also called gastric cancer, cancer cells usually begin in the inner lining of your stomach. They then grow deeper into your stomach walls as the cancer develops. It’s common worldwide but rare in the U.S. Common stomach cancer symptoms like unexplained weight loss and stomach pain often don’t appear in the early stages.
With stomach cancer — also called gastric cancer — cancer cells grow out of control in your stomach. Cancer can form anywhere in your stomach. In the U.S., most cases of stomach cancer involve abnormal cell growth in the place where your stomach meets your esophagus (gastroesophageal junction). In other countries, where gastric cancer is more common, cancer usually forms in the main part of your stomach.
About 95% of the time, stomach cancer starts in your stomach lining and progresses slowly. Untreated, it can form a mass (tumor) and grow deeper into your stomach walls. The tumor may spread to nearby organs like your liver and pancreas.
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Anyone can develop stomach cancer, but certain demographic factors may increase your risk. You’re more likely to get stomach cancer if:
Stomach cancer is one of the most common cancers worldwide but is seen less often in the U.S. Only about 1.5% of stomach cancers get diagnosed each year in the U.S., where cases have been declining steadily for the past 10 years.
Stomach cancer doesn’t typically cause symptoms during the early stages. Even the most common early signs of stomach cancer — often unexplained weight loss and stomach pain — don’t usually show up until the cancer is more advanced.
Symptoms of stomach cancer include:
Many of these symptoms are common in other conditions, too. See your provider to check if your symptoms are a sign of stomach cancer or another disease.
Your provider may be able to feel a mass in your stomach during a physical exam depending on how advanced the cancer is. More often, however, symptoms involve recognizing sensations in your stomach. Your stomach may frequently feel swollen, full or painful. The pain may start as mild and then get more intense as the disease progresses.
Stomach cancer forms when there’s a genetic mutation (change) in the DNA of your stomach cells. DNA is the code that tells cells when to grow and when to die. Because of the mutation, the cells grow rapidly and eventually form a tumor instead of dying. The cancer cells overtake healthy cells and may spread to other parts of your body (metastasize).
Researchers don’t know what causes the mutation. Still, certain factors seem to increase the likelihood of developing stomach cancer. They include:
Several genetic conditions are associated with increased gastric cancer risk, including:
Stomach cancer is more common in people with Type A blood, although researchers aren’t sure why.
Your provider will review your medical history, ask about your symptoms and perform a physical exam that may involve feeling for a mass in your stomach. They may order several tests to diagnose and stage stomach cancer.
Staging allows your provider to assess how much the cancer has spread. With stomach cancer, staging ranges from 0 (zero) to IV (four). Stage 0 means the cancer hasn’t spread beyond your stomach lining. Stage IV means that it’s spread to other organs.
Providers don’t screen for stomach cancer in the U.S. because it’s so rare. Still, if you have a condition that increases your risk, your provider may recommend regular procedures like an upper endoscopy to detect cancerous changes. Ask your provider about their recommendations based on your risk.
Treatment depends on how far your cancer’s spread, your health and treatment preferences. It often involves a care team that includes your primary care provider, a cancer specialist (oncologist) and a gastrointestinal specialist (gastroenterologist). They can advise you on treatment options.
Depending on how much the cancer’s spread, your provider may recommend surgery to remove precancerous cells, a tumor, or all or part of your stomach.
Additional treatments attack cancer cells directly.
You can’t prevent stomach cancer, but you can reduce your risk if you:
Stomach cancer can be cured if it’s in the early stages. Often, though, diagnosis happens in later stages once symptoms begin. Ask your provider about the factors that play a role in your treatment outcomes.
The outlook for stomach cancer depends on the stage of cancer. People in the early stages of stomach cancer have a much better prognosis than those at a later stage. The 5-year survival rate for stomach cancer may be as high as 70% (for little spread) or as low as 6% (for advanced spread).
Speak with your provider for a more accurate assessment of your prognosis. The type of cancer you have, its spread, your health and how your cancer responds to treatment all shape your prognosis.
If you’re at increased risk of stomach cancer, speak with your provider about the pros and cons of regular screenings. Otherwise, keep tabs on your symptoms. Many of the symptoms associated with stomach cancer may be signs of another condition. Only your provider can make a definitive diagnosis.
See your provider if you have symptoms like stomach pain and unexplained weight loss with or without symptoms, like:
A note from Cleveland Clinic
Stomach cancer isn’t always preventable, but it may be treatable if caught early. Depending on your cancer diagnosis, your provider may recommend surgery to remove cancer cells or tumors. They may suggest a combination of treatments that can kill or shrink the cancer cells. Ultimately, your prognosis depends on multiple factors you can discuss with your provider. Don’t hesitate to ask about treatment options, including their benefits and risks. Seek your providers’ guidance on what your cancer diagnosis means for you.
Last reviewed by a Cleveland Clinic medical professional on 05/17/2022.
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