Breast cancer begins in the breast and spreads first to the lymph nodes of the armpit (axilla). When a breast lump is found to contain cancer, and if the cancer has not spread beyond the nodes of the axilla to distant sites, it is often removed surgically.
In many cases of breast cancer, removal of the entire breast is unnecessary. Removal of only a small lump of tissue containing the cancer (lumpectomy) along with the nodes that drain the breast (axillary node dissection), followed by radiation therapy to the breast, is all that is required.
