What happens if breast cancer is not treated?

The course varies by breast cancer type, grade, hormone and other tumour features, and the person's health. A tumour can enlarge within the breast and affect the skin or nipple. Cancer cells may enter nearby lymph nodes and, later, travel through the bloodstream or lymphatic system to organs such as bone, liver, lung, or brain. Possible effects include a breast or armpit lump, breast skin changes, pain, ulceration, breathlessness, bone pain, or neurological symptoms. A breast lump is a common presentation of breast cancer, but many breast lumps are caused by conditions that are not cancer.

Arrange assessment with a breast or oncology team rather than waiting for symptoms to settle. Examination, breast imaging, and a biopsy may identify the cancer type and guide treatment. Options can include surgery, radiotherapy, hormone therapy, targeted medicines, immunotherapy, or chemotherapy, depending on the tumour and its spread. If a previous diagnosis was made, ask the team how quickly treatment should start and what symptom changes to report.

Seek urgent medical help for severe breathlessness, new confusion, sudden weakness, uncontrolled bleeding, or rapidly worsening pain. Contact a clinician promptly for a new breast or armpit lump, persistent skin or nipple change, a wound that does not heal, or swelling that is increasing. These findings need assessment; they do not establish the cause by themselves.

Ask what the biopsy shows, whether lymph nodes are involved, whether testing for inherited gene changes is relevant, and which treatments address the breast tumour or disease elsewhere. Ask how side effects will be managed and which symptoms require same-day advice.