Are there different types of breast cancer?
Cancer is not a single disease; there are many different types depending on what type of cell in the body has caused the cancer. In a healthy body the cells (skin cells, liver cells, blood cells etc) divide and multiply in a controlled way. Sometimes cells divide in an uncontrolled way and become abnormal which creates a mass of irregular cells. This mass of cells is called a tumour. Tumours can be harmless (benign) or cancerous (malignant). Cancerous or malignant cells have the ability to invade and damage other tissues by forming new colonies of abnormal cells called secondary growths or metastases. Cancer of the breast is defined according to the part of the breast where the tumour begins. The breast is made up of sections called lobes and lobules which are connected by ducts. Cancer can be ductular ie arising from the ducts, or lobular ie arising from the lobes or lobules. If a cancer spreads to other parts of the body it is called metastatic.
There are two main places in the breast where cancer can occur: the lobules (the milk-producing tissue) and the ducts (which carry the milk to the nipple). • Ductal carcinoma in situ means an early cancer in the milk ducts. It can be detected by mammograms and is normally easy to cure. • Invasive ductal carcinoma means a cancer that started in the milk ducts but has now spread beyond them. • Lobular carcinoma in situ is not considered to be cancer. It is a pre-cancerous condition. Most women with lobular carcinoma in situ do not get breast cancer, but they have an increased risk of getting it, so they are given frequent checkups. • Invasive lobular carcinoma is a cancer that starts in the lobules and has spread. These can be difficult to diagnose as they do not always form a lump or show up on mammograms.
