Treatment for stomach cancer
Targeted cancer drugs work by targeting the differences in cancer cells that help them to grow and survive. Other drugs help the immune system to attack cancer. These are called immunotherapy.
Some drugs work in more than one way. So they are targeted as well as working with the immune system.
If you have advanced cancer, your doctor will test a sample (biopsy) of your cancer for certain proteins. They usually test a sample of your stomach cancer tissue from when you were first diagnosed. The results of the tests show whether a targeted or immunotherapy cancer drug is suitable for you.
Trastuzumab has the brand name Herceptin. Or you might have a biosimilar such as Ontruzant. A biosimilar is a very similar copy of the original drug, but it is not exactly the same. Biosimilars undergo strict testing to check they work just as well as the original drug.
Trastuzumab is a monoclonal antibody. Monoclonal antibodies work by attaching to proteins on or in cancer cells.
Trastuzumab is a treatment for cancers that have large amounts of a protein called human epidermal growth factor receptor 2 (HER2). Human epidermal growth factor 2 (HER2) is a protein that makes cells grow and divide.
Some stomach cancers have large amounts of HER2 protein. These are called HER2 positive cancers. Trastuzumab works by locking onto HER2 on the cancer cells. The aim is to stop the cells from growing and kills them.
Trastuzumab only works if your cancer is HER2 positive.
You might have it with chemotherapy for advanced stomach cancer if:
if you have not had any other treatment for advanced cancer
your cancer is HER2 positive
Read more about trastuzumab and the side effects
Nivolumab is a type of immunotherapy called a checkpoint inhibitor. It works by blocking the PD-L1 protein. This protein stops the immune system from working properly and attacking cancer cells. Nivolumab helps to make your immune system find and kill cancer cells.
You might have nivolumab for advanced stomach cancer if:
you have not had any other treatment for advanced cancer
your cancer has a large amount of PD-L1 protein
your cancer is HER2 negative
You have this drug with chemotherapy.
Read more about nivolumab and the side effects
Pembrolizumab is another checkpoint inhibitor. You might have it for advanced stomach cancer that has started to grow again during or after one treatment. It is for people whose cancer has gene changes which means it is called:
(MSI high)
You may have this drug for up to 2 years if there are no signs of your cancer growing.
Find out more about pembrolizumab and the side effects
Ramucirumab is another type of monoclonal antibody. It targets a different protein – vascular endothelial growth factor receptor 2 (VEGFR2). This drug works by blocking the protein so that the cancer can’t develop the blood vessels it needs to grow.
Some studies have shown that ramucirumab is beneficial for people with advanced stomach cancer, when other treatments haven’t worked. At the moment it’s not routinely available in the UK.
You can have targeted and immunotherapy cancer drugs as:
a drip in your arm
an injection under the skin
a tablet
You have these drugs with chemotherapy every 2 to 3 weeks.
The side effects of targeted and immunotherapy cancer drugs are different depending on the drug you’re having. Not everyone gets all side effects.
The side effects you have depend on:
which drug you have
whether you have it alone or with other drugs
the amount of drug you have (the dose)
your general health
A side effect may get better or worse during your course of treatment. Or more side effects may develop as the treatment goes on. For more information about the side effects of your treatment, go to the individual drug pages.
Researchers are looking at many types of targeted drugs and immunotherapies for stomach cancer. Some of these drugs are already used to treat other cancers, and some are new.
Researchers are looking at giving these drugs on their own or with chemotherapy.
Find out more about research for stomach cancer
Treatment for stomach cancer can be difficult to cope with. Tell your doctor or nurse about any problems or side effects you have. Your nurse will give you numbers to call if you have any problems at home.
Last reviewed: 07 Jul 2025
Next review due: 07 Jul 2028
Your treatment depends on whereabouts your cancer is in the stomach. How big it is, whether it has spread anywhere else in your body and your general health.
Chemotherapy uses anti cancer drugs to destroy cancer. You might have it before or after surgery for stomach cancer, or as your main treatment if your cancer is advanced.
Research trials aim to find out if new treatments are safe and better than those currently available for stomach cancer.
Coping with cancer can be difficult. Help and support is available. There are things you can do, people to help and ways to cope with a diagnosis of stomach cancer.
Advanced stomach cancer means that a cancer that began in the stomach has spread to at least one other part of the body, such as the liver or lungs.
Stomach cancer is cancer that starts anywhere inside the stomach or the stomach wall. It’s also called gastric cancer.
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