Overview
Breast cancer is a disease in which abnormal breast cells grow out of control and form tumours. If left unchecked, the tumours can spread throughout the body and become fatal.
Breast cancer cells begin inside the milk ducts and/or the milk-producing lobules of the breast. The earliest form (in situ) is not life-threatening. Cancer cells can spread into nearby breast tissue (invasion). This creates tumours that cause lumps or thickening.
Invasive cancers can spread to nearby lymph nodes or other organs (metastasize). Metastasis can be fatal.
Treatment is based on the person, the type of cancer and its spread. Treatment combines surgery, radiation therapy and medications.
Information presented on this page has been replicated from the linked WHO fact sheet. Please always refer to the original source on who.int for the latest version. Last update: March 2024
