Breast cancer is the uncontrolled growth of abnormal cells which form a tumour in the breast. Breast cancer tumours may grow for months or years without causing breast cancer symptoms or any sign of breast cancer. Most breast cancers develop in the milk duct (ductal breast cancer) or the lobes (lobular breast cancer). Inflammatory breast cancer is a rare, usually metastatic form of breast cancer characterized by swollen, sore, warm breasts due to blockage of lymphatic flow.
Breast cancer diagnosis
At diagnosis, the cancer cells may be limited to the breast or may have spread to the lymph nodes (immune glands) and possibly other tissues through the process of metastasis. The tumour size at diagnosis is a good predictor of the likelihood of metastasis: tumours 1 cm or smaller are unlikely to have metastasized while tumours 5 cm or larger will have likely metastasized beyond the breast.
Approximately 190,000 women are diagnosed with breast cancer every year in the United States. Advances in breast cancer treatment have reduced the number of deaths from breast cancer by about 2% per year over the last 10 years. However, about 40,000 people still die annually from breast cancer. Breast cancer awareness is at an all-time high since approximately one woman in every eight will develop breast cancer. Breast cancer research continues to advance the understanding of breast cancer prevention.