How does HER2-targeted therapy work?

HER2 is a protein on the surface of some cancer cells. When a tumour has extra HER2 or unusually active HER2 signalling, those signals can encourage cells to grow. Testing a biopsy helps the team determine whether the tumour is HER2-positive and which treatment approach may fit.

HER2 antibody drugs can attach to the protein and block its signals, while also helping the immune system recognise the marked cell. Other medicines enter the cell or carry a drug payload directly to HER2-bearing cells. These approaches may be used alone or with chemotherapy, depending on the cancer, stage, previous treatment, and overall health. Breast and stomach cancers are among the settings where HER2-directed treatment may be considered.

Ask which HER2 test was used and whether the result is clear. Before treatment, your team may review heart health and other medicines; monitoring can continue during therapy because some HER2 medicines can affect the heart. Tell the team about breathlessness, swelling, palpitations, or a new persistent cough. Discuss how the medicine is given, whether it is combined with another treatment, and how response will be assessed.

Contact your oncology service promptly for new or worsening breathlessness, chest discomfort, fainting, marked swelling, or a fast or irregular heartbeat. Also report fever, severe diarrhoea, a widespread rash, or signs of an infusion reaction such as flushing and throat tightness. Follow the urgent instructions provided by your treatment centre.

What does my HER2 test show, and which medicine is being recommended? Will treatment be combined with chemotherapy or another drug? What heart checks are needed? Which symptoms require same-day advice, and how will we know whether treatment is helping?