Understand the Different Types of Breast Cancer

We can categorize types of breast cancers in several ways: By where they originate, by whether the cancer cells are isolated to one area or have spread, and by the tumor's hormonal status.

Origins of Breast Cancer

Breast cancer typically begins in the lobes, lobules, or ducts of the breast. When patients have abnormal cells in the milk duct, which have not spread, they are diagnosed with ductal carcinoma in situ (DCIS). DCIS is the most common type of breast cancer, although there is controversy about whether DCIS is really cancer and whether physicians should continue to treat it aggressively.

Lobular carcinoma (cancer) begins in the breast lobes or lobules and affects both breasts about 30 percent of the time. Lobular carcinoma in situ (LCIS) is not really cancer, but a condition that raises your risk of developing cancer.

Approximately 25 percent of women with LCIS will develop breast cancer at some point in their lives. LCIS is not visible on a mammogram; physicians typically find it during a biopsy for some other reason.

Cancer can also form in the muscles, fat, or blood vessels of the breast. The tissue type where cancer originates determines how a cancer will behave and influences treatment decisions.

Breast Cancer's Spread

Non-invasive cancer means cancer cells remain in their place of origin and not spread. DCIS and LCIS are both non-invasive cancers. In patients with invasive cancer, the cells have spread (metastasized) beyond the membrane that lines the ducts or lobules where the tumor originated. Invasive breast cancer is generally very serious.

Hormone Status of Breast Cancer

Some breast cancers need hormones to grow. These tumors have receptors for estrogen, progesterone, or both. If they have more receptors than normal, the cancer may grow quickly.

  • Estrogen receptor (ER) positive cancer is sensitive to estrogen.
  • progesterone receptor (PG) positive cancer is sensitive to progesterone.
  • hormone receptor (HR) negative doesn't have hormone receptors so treatments that block hormones have no effect.

If you have ER or PG positive breast cancers, your oncologist may recommend hormone therapy, which removes hormones or blocks their action and stops cancer cells from growing.

Breast Cancer Treatment

Because there are so many types of breast cancers, there is no one-size-fits-all treatment. Each woman's oncologist recommends an individual course of treatment, which may include surgery, radiation, chemotherapy, or hormone therapy-alone or in combination.


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National Cancer Institute. "What You Need To Know About Breast Cancer." Web. 15 October 2009. http://www.cancer.gov/cancertopics/wyntk/breast

Mayo Clinic. "Ductal carcinoma in situ (DCIS)." Web. 23 June 2011.

Mayo Clinic. "Breast cancer types: What your type means." Web. 9 February 2012. http://www.mayoclinic.com/health/breast-cancer/HQ00348

Nelson, Roxanne. "Problems With DCIS Misdiagnosis: When Cancer Is Not Cancer." Medscape Medical News. Web. 29 July 2010.

Stanford Medicine. "Lobular Carcinoma in situ (LCIS)." Web.