Disease & Drug Info

Types of Breast Cancer

Did you know there are different kinds of breast cancer? Use this guide to learn more about the types of breast cancer, how they are determined, and how they are classified.

After a breast cancer diagnosis, your medical team will need to determine your specific type of breast cancer. To do this, an in-depth evaluation will be done on a tissue sample collected from your breast biopsy, or on the tumor itself after your breast cancer surgery.

There are several factors that are considered, including:

  • Origin point of the cancer cells
  • How the breast cancer cells look under the microscope
  • How the cancer cells react to hormones
  • The breast cancer cells’ genetic makeup

BREAST CANCER TYPES

Breast cancer occurs in two broad categories: invasive and noninvasive. Invasive (or, infiltrating) breast cancer, means the disease has spread into the fatty tissue of the breast.  Noninvasive (in situ) means that the cancerous cells are still confined within the gland.  

Sometimes, there can be a combination of different cancer types within a single breast tumor.

COMMON CATEGORIES OF BREAST CANCER

There are certain breast cancers that are more common than others. Some specific types of common breast cancer include:

Ductal carcinoma in situ

Ductal carcinoma in situ (DCIS) is a non-invasive breast cancer, where abnormal cells have been contained in the lining of the breast milk duct. DCIS isn’t considered life-threatening, but it can progress into an invasive breast cancer.

Lobular carcinoma in situ

Lobular carcinoma in situ (LCIS) is actually not considered cancer or a pre-cancer because it doesn’t turn into invasive cancer, if untreated. Rather, LCIS is an indication that a person is at a higher risk of getting breast cancer later on.

Invasive ductal carcinoma

Invasive ductal carcinoma (IDC) means that abnormal cells that originated in the lining of the breast milk duct have invaded surrounding tissue. Over time, IDC can spread to the lymph nodes and possibly to other areas of the body. This is the most common type of invasive breast cancer, accounting for approximately 80% of all invasive breast cancers.

Invasive lobular carcinoma

Invasive lobular carcinoma (ILC) starts in the milk-producing glands (lobules) and can spread to other parts of the body. It is the second most common form of invasive breast cancer, accounting for 10 to 15% of breast cancer cases.

Invasive breast cancers will require an oncology team to create a treatment plan using one or more of the following: 

LESS COMMON TYPES OF BREAST CANCER

Inflammatory breast cancer

A less common type of breast cancer, accounting for just 1-3% of all cases, is inflammatory breast cancer (IBC). IBC often appears to be an infection (red, swollen and inflamed breast) but is actually cancer that is blocking lymphatic vessels in the skin and breast tissue, causing a buildup of fluid (lymph).

A few other rare types of breast cancer are diagnosed each year, including:

Paget disease of the nipple

This type of breast cancer starts in the breast ducts and spreads to the skin of the nipple and then to the areola, the dark circle around the nipple. This type of breast cancer only accounts for about 1% of all cases of breast cancer.

Phyllodes tumor

Phyllodes tumors are rare breast tumors. These tumors develop in the connective tissue (stroma) of the breast and grow in a leaf-like pattern. Although phyllodes tumors tend to grow quickly, they rarely spread outside the breast.

Angiosarcoma

Angiosarcoma is a cancer in the inner lining of blood vessels that can occur in any part of the body. This form of cancer is very rare.