Breast Cancer

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Types of Breast Cancer

There are many types of breast cancer, and many different ways to describe them. It’s easy to get confused.

A breast cancer's type is determined by the specific cells in the breast that become cancer.

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Ductal or lobular carcinoma

Most breast cancers are carcinomas, which are tumors that start in the epithelial cells that line organs and tissues throughout the body. When carcinomas form in the breast, they are usually a more specific type called adenocarcinoma, which starts in cells in the ducts (the milk ducts) or the lobules (glands in the breast that make milk).

In situ vs. invasive breast cancers

The type of breast cancer can also refer to whether the cancer has spread or not. In situ breast cancer (ductal carcinoma in situ or DCIS) is a pre-cancer that starts in a milk duct and has not grown into the rest of the breast tissue. The term invasive (or infiltrating) breast cancer is used to describe any type of breast cancer that has spread (invaded) into the surrounding breast tissue.

Ductal carcinoma in situ (DCIS)

Ductal carcinoma in situ (DCIS; also known as intraductal carcinoma) is a non-invasive or pre-invasive breast cancer. 

Invasive breast cancer (ILC or IDC)

Invasive (or infiltrating) breast cancer has spread into surrounding breast tissue. The most common types are invasive ductal carcinoma and invasive lobular carcinoma. Invasive ductal carcinoma makes up about 70-80% of all breast cancers. 

Special types of invasive breast cancers

Some invasive breast cancers have special features or develop in different ways that influence their treatment and outlook. These cancers are less common but can be more serious than other types of breast cancer.

Triple-negative breast cancer

Triple-negative breast cancer is an aggressive type of invasive breast cancer in which the cancer cells don’t have estrogen or progesterone receptors (ER or PR) and also don’t make any or too much of the protein called HER2. (The cells test "negative" on all 3 tests.) It accounts for about 15% of all breast cancers and can be a difficult cancer to treat.

Inflammatory breast cancer

Inflammatory breast cancer is an aggressive type of invasive breast cancer in which cancer cells block lymph vessels in the skin, causing the breast to look "inflamed." It is rare and accounts for about 1% to 5% of all breast cancers.

Less common types of breast cancer

There are other types of breast cancers that start to grow in other types of cells in the breast. These cancers are much less common, and sometimes need different types of treatment.

Paget disease of the breast

Paget disease of the breast is rare, accounting for only about 1-3% of all cases of breast cancer.  It starts in the breast ducts and spreads to the skin of the nipple and then to the areola (the dark circle around the nipple). 

Angiosarcoma

Sarcomas of the breast are rare making up less than 1% of all breast cancers. Angiosarcoma starts in cells that line blood vessels or lymph vessels. It can involve the breast tissue or the skin of the breast. Some may be related to prior radiation therapy in that area. 

Phyllodes tumor

Phyllodes tumors are rare breast tumors. They develop in the connective tissue (stroma) of the breast, in contrast to carcinomas, which develop in the ducts or lobules. Most are benign, but there are others that are malignant (cancer).

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References

The American Cancer Society medical and editorial content team

Our team is made up of doctors and oncology certified nurses with deep knowledge of cancer care as well as editors and translators with extensive experience in medical writing.

Anders CK and Carey LA. ER/PR negative, HER2-negative (triple-negative) breast cancer. UpToDate website. https://www.uptodate.com/contents/er-pr-negative-her2-negative-triple-negative-breast-cancer. Updated June 06, 2019. Accessed July 23, 2019. 

Calhoun KE, Allison KH, Kim JN et al. Chapter 62: Phyllodes Tumors.  In: Harris JR, Lippman ME, Morrow M, Osborne CK, eds. Diseases of the Breast. 5th ed. Philadelphia, Pa: Lippincott-Williams & Wilkins; 2014.

Dillon DA, Guidi AJ, Schnitt SJ. Ch. 25: Pathology of invasive breast cancer. In: Harris JR, Lippman ME, Morrow M, Osborne CK, eds. Diseases of the Breast. 5th ed. Philadelphia, Pa: Lippincott-Williams & Wilkins; 2014.

Esteva FJ and Gutiérrez C. Chapter 64: Nonepithelial Malignancies of the Breast. In: Harris JR, Lippman ME, Morrow M, Osborne CK, eds. Diseases of the Breast. 5th ed. Philadelphia, Pa: Lippincott-Williams & Wilkins; 2014.

Henry NL, Shah PD, Haider I, Freer PE, Jagsi R, Sabel MS. Chapter 88: Cancer of the Breast. In: Niederhuber JE, Armitage JO, Doroshow JH, Kastan MB, Tepper JE, eds. Abeloff’s Clinical Oncology. 6th ed. Philadelphia, Pa: Elsevier; 2020.

Jagsi R, King TA, Lehman C, Morrow M, Harris JR, Burstein HJ. Chapter 79: Malignant Tumors of the Breast. In: DeVita VT, Lawrence TS, Lawrence TS, Rosenberg SA, eds. DeVita, Hellman, and Rosenberg’s Cancer: Principles and Practice of Oncology. 11th ed. Philadelphia, Pa: Lippincott Williams & Wilkins; 2019.

National Cancer Institute. Inflammatory Breast Cancer. 2016. Accessed at https://www.cancer.gov/types/breast/ibc-fact-sheet on August 30, 2021.

National Comprehensive Cancer Network (NCCN). Practice Guidelines in Oncology: Breast Cancer. Version 7.2021. Accessed at https://www.nccn.org/professionals/physician_gls/pdf/breast.pdf on August 30, 2021.

Nora M. Hansen. Chapter 63: Paget's Disease. In: Harris JR, Lippman ME, Morrow M, Osborne CK, eds. Diseases of the Breast. 5th ed. Philadelphia, Pa: Lippincott-Williams & Wilkins; 2014.

Overmoyer B and Pierce LJ. Chapter 59: Inflammatory Breast Cancer. In: Harris JR, Lippman ME, Morrow M, Osborne CK, eds. Diseases of the Breast. 5th ed. Philadelphia, Pa: Lippincott-Williams & Wilkins; 2014.

Last Revised: November 19, 2021

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