Trastuzumab only works for people with a stomach cancer that has high levels of a protein called HER2. Between 10 and 15 out of every 100 people with stomach cancer (10 to 15%) have a HER2-positive cancer. Tests can be done on tissue taken at a biopsy or during surgery to find out if the cancer cells have high levels of HER2.
Trastuzumab attaches to the HER2 proteins on the surface of the cancer cells. This stops the cancer cells from dividing and growing.
How trastuzumab is given
Immunotherapy treatments use the immune system to find and attack cancer cells. Some types of immunotherapy are also a targeted therapy.
You may be offered immunotherapy drugs such as nivolumab, or pembrolizumab. These are not widely available through the NHS. When a drug is not available through the NHS, it may still be possible to have it in some situations. Your cancer doctor can tell you more about this.
Immunotherapy treatment has been shown to be helpful for treating a few different cancers. Currently, immunotherapy is not commonly used to treat stomach cancer. But you may be offered it as part of a clinical trial. Doctors are also testing other targeted therapy drugs in clinical trials.