Does HER2-targeted therapy treat stomach cancer?

HER2 is a protein that can send growth signals to cancer cells. A laboratory test on tumour tissue checks whether HER2 is present at a level that could make targeted treatment useful. A positive result does not describe every feature of the cancer, and a negative result means this particular treatment may not be suitable.

Treatment may be combined with other medicines, depending on whether the cancer can be removed, how far it has spread, previous treatment, and your general health. The aim may be to shrink or control the cancer, relieve symptoms, or support treatment before or after another approach. Your oncology team will explain the plan in the context of your [Stomach Cancer](/conditions/stomach-cancer/).

Ask whether HER2 testing has been performed on a suitable tissue sample and what the result means for your treatment choices. If the sample is limited or the result is unclear, the team may discuss another sample or an additional laboratory method. Review the proposed [HER2-Targeted Therapy](/treatments/systemic-therapy/her2-targeted-therapy/) schedule, possible effects, monitoring, and how it fits with surgery, chemotherapy, immunotherapy, or radiotherapy if those are being considered.

Contact your oncology team promptly for new breathing difficulty, chest discomfort, fainting, severe weakness, facial or throat swelling, or a sudden widespread rash during treatment. These symptoms can need urgent assessment. Also report persistent vomiting, inability to keep fluids down, fever, or diarrhoea, because your team may need to check for dehydration, infection, or a treatment effect.

What did my HER2 test show, and which tissue was tested? What is the goal of treatment in my situation? Which other treatments might be combined with it? How will my heart, lungs, and general health be monitored? Which symptoms should make me call the treatment team the same day?