What stomach cancer is
Stomach cancer starts when malignant cells form in the lining of the stomach. The stomach is a muscular organ that holds food and begins breaking it down during digestion. Cancer can develop in any part of the stomach and may spread to nearby organs or lymph nodes if not caught early.
Most stomach cancers are adenocarcinomas, which means they start in the glandular cells that line the stomach and produce digestive juices. Other types are less common but include squamous cell carcinoma and neuroendocrine tumors. The type matters because it affects how doctors treat the cancer and what to expect.
Stomach cancer is sometimes called gastric cancer. It often develops slowly over many years, sometimes without obvious symptoms in the early stages. This is why people diagnosed with stomach cancer may not realize they have it until it has already grown or spread.
Key Takeaways
- Stomach cancer starts in the cells lining the stomach and most commonly is a type called adenocarcinoma.
- Early stomach cancer often has no symptoms, which is why it is frequently found at a later stage.
- Doctors use endoscopy, imaging tests, and biopsies to diagnose stomach cancer and determine how far it has spread.
- Risk factors include infection with H. pylori bacteria, smoking, heavy alcohol use, and a family history of stomach cancer.
- Treatment options depend on the stage and may include surgery, chemotherapy, radiation, or a combination of these.
Symptoms and when to see a doctor
Early stomach cancer often causes no symptoms at all. When symptoms do appear, they can be vague and easy to mistake for other conditions like heartburn or the flu. Common symptoms include persistent indigestion, loss of appetite, feeling full quickly after eating, nausea, vomiting, and abdominal pain or discomfort.
More advanced stomach cancer may cause weight loss without trying, difficulty swallowing, vomiting blood, or dark or bloody stools. If you have any of these symptoms lasting more than a few weeks, especially if they are getting worse, contact your doctor. Your doctor can run tests to find out what is causing the symptoms.
Some people have no symptoms and stomach cancer is found by chance during tests for another reason. This is one reason why screening programs exist in some countries where stomach cancer is more common, though routine screening is not standard in most places.
How doctors diagnose stomach cancer
If your doctor suspects stomach cancer, the first step is usually an upper endoscopy. During this procedure, a thin tube with a camera on the end is passed down your throat into your stomach. This allows the doctor to see the stomach lining directly and take small tissue samples (a biopsy) if abnormal areas are found. A pathologist then examines the tissue under a microscope to check for cancer cells.
Once cancer is confirmed, doctors order imaging tests to see how far it has spread. These may include a CT scan, MRI, or PET scan of the abdomen and chest. An ultrasound may also be used. These tests help determine the stage of the cancer — how large it is and whether it has reached nearby lymph nodes or distant organs.
Blood tests are often done as well, though they cannot diagnose stomach cancer on their own. They can show how well your liver and kidneys are working, which matters for treatment planning. Your doctor may also perform an endoscopic ultrasound, which combines endoscopy with ultrasound to get a detailed view of the stomach wall and nearby lymph nodes.
Risk factors for stomach cancer
Infection with H. pylori bacteria is one of the strongest risk factors for stomach cancer. This bacterium lives in the stomach lining and can cause chronic inflammation. Many people carry H. pylori without symptoms, but over decades it can increase cancer risk. Your doctor can test for this infection and treat it with antibiotics if found.
Other risk factors include smoking, heavy alcohol use, obesity, and a diet high in processed or salt-cured foods. Family history matters too — if a close relative had stomach cancer, your risk is higher. Certain genetic conditions, such as hereditary diffuse gastric cancer syndrome, also increase risk. Some people with a family history may be offered genetic testing.
Having chronic stomach inflammation from conditions like pernicious anemia or previous stomach surgery can raise risk as well. Age is a factor; stomach cancer is more common in people over 60. Understanding your risk factors can help you and your doctor decide whether screening or closer monitoring makes sense for you.
Stages of stomach cancer
Stomach cancer is staged from 0 to IV based on how deep the cancer has grown into the stomach wall and whether it has spread to lymph nodes or other organs. Stage 0 means abnormal cells are present but have not yet become invasive cancer. Stage I means the cancer is in the stomach lining or muscle layer but has not spread to lymph nodes.
Stage II and Stage III cancers have grown deeper into the stomach wall and have spread to nearby lymph nodes. The more lymph nodes involved, the higher the stage. Stage IV means the cancer has spread to distant organs such as the liver, lungs, or peritoneum (the lining of the abdominal cavity).
The stage is crucial because it guides treatment decisions and helps predict outcomes. Early-stage cancers that have not spread beyond the stomach have better outcomes than advanced cancers. Your doctor will explain your stage and what it means for your treatment plan.
Treatment options for stomach cancer
Surgery is the main treatment for stomach cancer that has not spread to distant organs. The surgeon may remove part of the stomach (partial gastrectomy) or the entire stomach (total gastrectomy), along with nearby lymph nodes and sometimes parts of other organs. The goal is to remove all the cancer while preserving as much stomach function as possible.
Chemotherapy uses drugs to kill cancer cells throughout the body. It may be given before surgery to shrink the tumor, after surgery to destroy any remaining cancer cells, or as the main treatment if surgery is not an option. Radiation therapy uses high-energy beams to target cancer cells and is sometimes combined with chemotherapy.
Newer treatments called targeted therapy and immunotherapy work differently than traditional chemotherapy. Targeted therapy drugs attack specific features of cancer cells, while immunotherapy helps your immune system recognize and fight cancer. Your doctor will recommend a treatment plan based on your stage, overall health, and other factors.
Life after a stomach cancer diagnosis
After treatment, you will have follow-up appointments with your oncologist to watch for signs that cancer has returned. These visits typically include physical exams and imaging tests. The schedule depends on your stage and type of treatment, but follow-up usually continues for several years.
If your stomach was removed or partially removed, you may need to adjust how you eat — eating smaller meals more frequently and avoiding certain foods that cause discomfort. A dietitian can help you plan meals that provide proper nutrition. Some people experience side effects from treatment that persist, such as fatigue or digestive changes, and your doctor can suggest ways to manage these.
Support groups, whether in person or online, connect you with others who have had stomach cancer. Talking with people who understand what you are going through can be valuable. Your medical team can point you toward resources in your area or online.
Frequently Asked Questions
Is stomach cancer hereditary?
Most stomach cancer is not inherited, but some families carry genetic mutations that increase risk significantly. The most well-known is a mutation in the CDH1 gene, which causes hereditary diffuse gastric cancer syndrome. If you have a family history of stomach cancer, ask your doctor whether genetic testing or counseling might be right for you.
Can stomach cancer be prevented?
You cannot prevent stomach cancer with certainty, but you can lower your risk. Getting tested for and treating H. pylori infection reduces risk. Not smoking, limiting alcohol, maintaining a healthy weight, and eating a diet rich in fruits and vegetables may also help. In countries with high stomach cancer rates, screening programs have reduced deaths.
What is the survival rate for stomach cancer?
Survival rates vary widely depending on the stage at diagnosis, the type of cancer, and how well it responds to treatment. Early-stage cancers have much better outcomes than advanced cancers. Your doctor can discuss your individual prognosis based on your specific situation, though outcomes are difficult to predict.
Will I need chemotherapy even if surgery removes all the cancer?
Many people receive chemotherapy after surgery to reduce the risk that cancer will return, even if the surgeon removed all visible cancer. This is called adjuvant chemotherapy. Your doctor will recommend this based on the stage and other features of your cancer. The goal is to destroy any cancer cells that may have spread but are too small to see.
Can I eat normally after stomach surgery?
After stomach removal or partial removal, your eating habits will change. You will likely need to eat smaller meals more often and may need to avoid certain foods that cause bloating, nausea, or dumping syndrome (rapid stomach emptying). A dietitian specializing in post-surgery nutrition can help you adjust and ensure you get enough calories and nutrients.