Types of breast cancer
Breast cancer occurs in two broad categories: invasive and noninvasive.
- Invasive (infiltrating) breast cancer: Cancerous cells break through normal breast tissue barriers and spread to other parts of the body through the bloodstream and lymph nodes.
- Noninvasive (in situ) breast cancer: Cancerous cells remain in a particular location of the breast, without spreading to surrounding tissue, lobules or ducts.
Breast cancer is also classified based on where in the breast the disease started (e.g., milk ducts, lobules), how the disease grows and other factors. The tabs on the left provide an overview of common breast cancer types, common subtypes and rare types.
Other types of breast cancer include sarcoma of the breast, metaplastic carcinoma, adenocystic carcinoma, phyllodes tumor and angiosarcoma.
Genomic research has also led to a more specific classification of breast cancers, based on their genes and proteins. Sixty percent of breast cancers are estrogen positive, for example, while 20 percent are HER2 positive and another 20 percent are triple-negative.