What Is Breast Cancer?
Breast cancer is an uncontrolled growth of breast cells that leads to the formation of a tumor. Some breast tumors are benign (non-cancerous) and do not cause harm. They grow slowly and do not spread to other areas of the body. Malignant breast tumors are cancerous; left unchecked cancer cells can make their way into the underarm lymph nodes, which provides a pathway for them to spread to other areas of the body.
Each breast has 15-20 sections, called “lobes,” connected by thin tubes called “ducts.” Breast cancers include:
- Ductal carcinoma, which begins in the ducts and is the most common type.
- Lobular carcinoma, which begins in the lobes and is found in both breasts more often than other types of breast cancer.
- Inflammatory breast cancer, which is rare.
- Recurrent breast cancer, which is cancer that has returned. It can occur in remaining breast tissue, but also in other sites such as the lungs, liver, bones or brain. Even if tumors are in a new location, it is still called breast cancer.