The short answer
Stomach cancer treatment depends on the stage. Surgery to remove part or all of the stomach is common, often with chemotherapy before or after. Radiation, targeted therapy, and immunotherapy are used in some cases.
Treatment depends on the stage of the stomach cancer.
Surgery to remove part or all of the stomach is common.
Chemotherapy is often used before or after surgery.
Radiation, targeted therapy, and immunotherapy are used in some cases.
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The full explanation.
The simple version
Stomach cancer treatment depends on the stage. Surgery to remove part or all of the stomach is common. It is usually paired with chemotherapy. Radiation, targeted therapy, and immunotherapy are used in some cases. The choice depends on the features of the tumor.
Surgery
Surgery to remove part or all of the stomach is called a gastrectomy. Nearby lymph nodes usually come out at the same time. Cancer can spread there first, so doctors check them closely. When only part of the stomach is removed, surgeons reconnect what remains to the intestine. This lets you keep eating. Meals often need to be smaller afterward. A dietitian can help you adjust.
Surgery removes part or all of the stomach and is common for stomach cancer.
Chemotherapy before and after surgery
Chemotherapy is often given before surgery. This can shrink the tumor and make it easier to remove. It is also given after surgery. This kills any cancer cells left behind. It lowers the chance the cancer returns. Doctors call this perioperative chemotherapy. It is now standard for many stomach cancers beyond the earliest stage.
Very early cancer
For the earliest stomach cancers, confined to the inner lining, doctors may remove the tumor using an endoscope. This is a thin, lighted tube passed down the throat. No incision is needed. This option only works for small, early tumors. Careful testing beforehand confirms whether it fits.
Radiation, targeted therapy, and immunotherapy
Radiation is used in some cases. It is often combined with chemotherapy. This is especially true when surgery cannot remove all the cancer. Targeted therapy attacks specific features of a tumor. Some stomach cancers have extra amounts of a protein called HER2. Drugs like trastuzumab can target it directly. Other targeted drugs, such as ramucirumab, block blood vessels that feed the tumor. Immunotherapy drugs, including nivolumab and pembrolizumab, help the immune system attack the cancer. Doctors use them for some advanced or recurrent cases.
Biomarker testing guides the plan
Before starting drug treatment, doctors usually test a piece of the tumor. They look for markers like HER2. They also check for signs that immunotherapy is likely to help. This is called biomarker testing. It matches a specific drug to a specific tumor, instead of guessing which treatment will work.
Eating during and after treatment
Surgery and other treatments can change how you eat, at least for a while. Smaller, more frequent meals are common advice after a gastrectomy. Some people need vitamin B12 shots afterward. The stomach normally helps absorb this vitamin. A dietitian who works with stomach cancer patients can make a real difference in comfort and nutrition during recovery.
What to ask your team
Ask what stage your stomach cancer is. Ask whether you will need part or all of your stomach removed. Ask whether chemotherapy will come before surgery, after it, or both. Ask whether your tumor has been tested for HER2 or other markers. Ask how treatment will affect eating, and whether a dietitian can help.
Clinical trials
Clinical trials test new treatments or new combinations of existing ones. For stomach cancer, especially at more advanced stages, a clinical trial can offer access to newer targeted drugs or immunotherapy combinations before they become widely available. Ask your team whether a trial fits your situation. Joining one is always your choice, and you can leave at any time.
Sources
Words to know
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Common questions
What are the main treatments?
Surgery, chemotherapy, radiation, targeted therapy, and immunotherapy. The plan depends on the stage and features of the cancer.
What does surgery involve?
Surgery removes part or all of the stomach along with nearby lymph nodes. When part is removed, the remaining stomach is reconnected so a person can still eat.
How is chemotherapy used?
Chemotherapy is often given before surgery to shrink the tumor, after surgery to lower the chance of return, or as a main treatment for advanced cancer.
What is biomarker testing for?
Testing the tumor can reveal features, such as HER2, that targeted therapy or immunotherapy can address, helping match treatment to the cancer.
Questions to ask your doctor
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Last updated: 2026-08-18Next planned review: 2027-07-07
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How this page was created
Cancer Explained does not originate medical claims. Every page restates guidance already published by the National Cancer Institute, the CDC, the USPSTF and the FDA, in plain language, with the source cited so you can check the original yourself. AI does the translating and organizing; automated checks test claims, citations, clarity and safety before anything publishes. We do not employ clinicians and do not intend to — our work is translation and navigation, not clinical judgment. Nothing here is personal medical advice, and no page can account for your particular situation.
Editorial status: Source checked — This page was written with AI assistance and checked line by line against the sources listed on it. That confirms the sources support what the page says. It is not a medical review, and it does not confirm the page is complete or right for your situation.
Human medical review: not completed. Pages here are not signed off by a clinician before they publish. That is not an oversight we are quietly working around: we restate published guidance and cite it, so the authority belongs to the source rather than to us, and every page names where its claims come from — you can verify us instead of trusting us. Where a volunteer clinician has reviewed a page, their name and credentials appear on it; where no name appears, no clinician has checked it. We are glad to have reviewers and are recruiting them, and we do not hold pages back waiting for one. Use this site to understand your situation and to ask better questions of the people treating you.
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