What is Breast Cancer?

Breast cancer is a disease characterized by the uncontrolled growth of cells in the breast. It encompasses various types, depending on which specific cells in the breast undergo cancerous changes.

The breast consists of three primary components: lobules, ducts, and connective tissue. Lobules are responsible for producing milk, while ducts are the channels that carry milk to the nipple. The connective tissue encompasses fibrous and fatty tissues, providing support and structure. The majority of breast cancers originate in either the ducts or lobules.

Breast cancer has the potential to spread beyond the breast through blood vessels and lymph vessels, a process known as metastasis. When breast cancer spreads to other parts of the body, it is considered metastatic breast cancer.

The most common types of breast cancer include:

1. Invasive ductal carcinoma: Cancer cells originate in the ducts and subsequently extend beyond the ducts into surrounding breast tissue. Invasive cancer cells can also metastasize to other areas of the body.

2. Invasive lobular carcinoma: Cancer cells begin in the lobules and then spread to adjacent breast tissues. Similar to invasive ductal carcinoma, these cancer cells can also metastasize to other parts of the body.

Additional, less common types of breast cancer include Paget's disease, medullary carcinoma, mucinous carcinoma, and inflammatory breast cancer.

Ductal carcinoma in situ (DCIS) is a non-invasive breast condition that may progress to invasive breast cancer. In DCIS, cancer cells are confined to the lining of the ducts and have not spread to other breast tissues.