Breast cancer is one of the most common cancers. Around one in nine women develop breast cancer at some stage in their lives. About 48,000 cases occur in the UK each year. Most develop in women over the age of 50 but younger women are sometimes affected. Breast cancer develops from a cancerous (malignant) cell which develops in the lining of a duct or lobule in one of the breasts.
This is a companion discussion topic for the original article at https://patient.info/cancer/breast-cancer-leaflet