What should you know about HER2 breast cancer?

HER2 is a protein that can send growth signals to cells. In some breast cancers, the tumour has extra HER2 protein or extra copies of the HER2 gene. That finding helps the team consider medicines designed to block HER2 signalling. HER2 status is separate from tumour size, lymph-node findings, hormone-receptor status, and whether cancer has spread, so the full pathology and staging picture matters.

Diagnosis commonly brings together a breast examination, imaging, a biopsy report, HER2 testing, hormone-receptor testing, and staging information. Depending on the situation, care may include surgery, HER2-directed treatment, chemotherapy, radiotherapy, hormone treatment, or a combination. Ask how each treatment fits the sequence, how heart health will be checked, and which side effects should be reported between appointments.

Call your treatment team promptly for fever, uncontrolled vomiting, new breathlessness, chest discomfort, fainting, or a marked reduction in urine. During treatment, report swelling, severe diarrhoea, allergic symptoms, or a new persistent cough. Sudden weakness, a seizure, a severe headache, or new confusion needs urgent assessment because cancer can sometimes affect the brain.

What are my HER2 and hormone-receptor results? What is known about the tumour stage and lymph nodes? Which treatment is recommended first, and why? What heart checks and other monitoring will I need?