Breast cancer is a type of cancer that starts in the cells of the breast. It can start in the milk-producing ducts, glandular tissue called lobules, or other breast cells and tissues. While about 10% of breast cancers are related to inherited abnormal genes, most (90%) are caused by acquired genetic changes that have not yet been identified. These changes cause the cells to grow abnormally and invade surrounding tissue, potentially leading to life-threatening consequences.
Different types of breast cancer are named according to their invasiveness in relation to the sites of the primary tumor. These include invasive ductal carcinoma, invasive lobular carcinoma, inflammatory breast cancer, and ductal carcinoma in situ. Symptoms of inflammatory breast cancer include swelling of the breasts, red or purple coloration of the skin, and formation of lumps or thickening of the skin. Postmenopausal combination hormone therapy has been linked to an increased risk of breast cancer, as well as an increased chance that it will only be detected at a more advanced stage.
Injectable progesterone, such as Depo-Provera, has also been linked to an increased risk of breast cancer, although this risk appears to decrease five years after ceasing use. The vast majority (85%) of breast cancers occur in women with no family history of the disease. However, lifestyle and personal behavior can also increase one's risk for developing breast cancer. These include smoking, drinking alcohol, being overweight or obese, not exercising regularly, and not breastfeeding.
It is important to be aware of the risk factors for breast cancer and to take steps to reduce your risk. This includes maintaining a healthy weight, exercising regularly, limiting alcohol consumption, avoiding smoking, and breastfeeding if possible.