Breast cancer is a kind of cancer originating from breast cells. It usually starts off in the inner lining of milk ducts (ductal carcinoma) or the lobules that supply them with milk (lobular carcinoma). As a malignant type of tumor, breast cancer is able to invade other parts of the body.
Breast cancer is the most common invasive cancer in females worldwide. It accounts for 16% of all female cancers and 22.9% of invasive cancers in women. 18.2% of all cancer deaths worldwide, including both males and females, are from breast cancer.
The first symptoms of breast cancer are usually an area of thickened tissue or a lump in the breast. Most lumps are not cancerous but should however be checked by a health care professional. Other unusual signs can also be detected, such as pain in the armpits or breast unrelated to the menstrual period, redness of the skin, rash around the nipple, swelling in the armpit, fluid leaking out of the nipple, skin starting to peel, scale or flake, etc.
Breast cancer comes from a mutation in the DNA of breast cells causing them to proliferate uncontrollably. The exact cause of this mutation is still unclear, but risk factors have been identified: prior history of breast disease or family history, age, race, reproductive and menstrual history, radiation exposure and dietary factors. However, the relative effect of these risk factors in any given case is variable and very difficult to determine.
The National Comprehensive Cancer Network (NCCN) lists different types of treatment for breast cancer: surgery, radiation therapy, chemotherapy, hormone therapy and monoclonal antibody therapy. Proton therapy, a state-of-the-art type of radiotherapy, is currently breaking new ground in the treatment of breast cancer, allowing to better spare healthy vital organs close to the tumor, such as the heart and lungs.