19 Nov 2013/
What is breast cancer, and who gets it?
Breast cancer is a disease in which a mass of cells forms a tumour in the breast. This can occur in the lobules (milk-producing glands) or ducts (which carry milk to the nipple) of the breast. Tumours can be malignant (cancerous) or benign (non-cancerous). Benign breast lumps are generally slow-growing and not harmful. Malignant tumours grow rapidly and have the potential to invade and spread into other tissues, while benign tumours do not. Both women and men can get breast cancer, although it mainly affects women (who have a 1 in 10 lifetime risk, versus a 1 in 1,000 risk for men; American Cancer Society 2013).
How does breast cancer develop?
Tumours arise when normal cells grow uncontrollably and ignore the signals that would usually tell them when to stop growing. This typically happens because of damage within these cells causing a mutation (a change in DNA sequence). Mutations can occur randomly, or be inherited and passed on from parents to children. Inherited mutations are quite rare and account for less than 10% of breast cancers. Depending on the impact of the mutation, the type of breast cancer will vary, as will the severity of the disease.
How can breast cancer be treated?
Some forms of breast cancer are easier to treat than others. There are several approaches, including surgical removal of the lump, radiotherapy, or drug treatment. For drugs, there are broadly two types. One is chemotherapy, which uses a single drug or several drugs in combination, to destroy the cancer cells. The second is a more specific approach, using drugs that target a particular abnormality in the cancer cells, stopping them from growing further. Drugs that reduce the levels of female hormones in the body, such as estrogen and progesterone, also fall under this category of specific therapy, because these hormones can stimulate cell growth in some breast cancer patients.
More aggressive forms of breast cancer have the ability to invade into areas other than their origin in the breast (this is known as metastasis), and to spread out through the lymphatic system or blood, into other tissues (like the bones, lungs or liver). If the cancer cells form tumours in other organs of patients, the cancer is much more difficult to treat, and the chance of it being cured is greatly reduced.