Understanding the Different Types of Breast Cancer

By: Lauren Meadows

The type of breast cancer diagnosed is dependent on the type of cells from which the cancer developed. The first step is determining the spread of the cancer.

Breast cancer that begins in the milk duct, referred to as ductal carcinoma, is considered a pre-cancer before it reaches the surrounding breast tissue. To consider breast cancer invasive means it has spread into the breast tissue. Invasive ductal carcinomas make up 70-80% of all breast cancer cases.

Types of less common, invasive breast cancers are Triple-negative and inflammatory, both are considered to be aggressive. Triple-negative earned its name from the test results it produces. These cancer cells lack estrogen and progesterone receptors and the protein HER2, causing a negative result on lab tests. This form accounts for 15% of all breast cancers.

Inflammatory breast cancer cells develop and block lymph vessels causing the skin to look ‘inflamed.’ This is one of the rarest forms of breast cancer, accounting for between one and five percent of all breast cancers. Some of these less-common types of breast cancer require special forms of treatment because of the unique cellular makeup.

Other uncommon types of breast cancer include Paget's disease of the breast, angiosarcoma, and phyllodes tumor. These are all unique in the way they develop and spread, including through connective tissues, blood and lymph vessels, and infiltrating the skin.

For more information about breast cancer types and developing treatment options, visit bcrf.org.