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Get answers to your Breast Cancer questions.
Dr. Tkaczuk’s Bio | Q&A Archive
Cancer - breast; Carcinoma - ductal; Carcinoma - lobular; DCIS; LCIS; HER2-positive breast cancer; ER-positive breast cancer; Ductal carcinoma in situ; Lobular carcinoma in situ
Breast cancer is a cancer that starts in the tissues of the breast. There are two main types of breast cancer:
In rare cases, breast cancer can start in other areas of the breast.
Breast cancer may be invasive or noninvasive. Invasive means it has spread from the milk duct or lobule to other tissues in the breast. Noninvasive means it has not yet invaded other breast tissue. Noninvasive breast cancer is called "in situ."
Many breast cancers are sensitive to the hormone estrogen. This means that estrogen causes the breast cancer tumor to grow. Such cancers have estrogen receptors on the surface of their cells. They are called estrogen receptor-positive cancer or ER-positive cancer.
Some women have what's called HER2-positive breast cancer. HER2 refers to a gene that helps cells grow, divide, and repair themselves. When cells (including cancer cells) have too many copies of this gene, they grow faster. Experts think that women with HER2-positive breast cancer have a more aggressive disease and a higher risk that the disease will return (recur) than women who do not have this type.
Over the course of a lifetime, 1 in 8 women will be diagnosed with breast cancer.
Risk factors you cannot change include:
Other risk factors include:
Breast implants, using antiperspirants, and wearing underwire bras do not raise your risk for breast cancer. There is no evidence of a direct link between breast cancer and pesticides.
The National Cancer Institute provides an online tool to help you figure out your risk of breast cancer. See:
Carlson RW, Allred DC, Anderson BO, Burstein HJ, Carter WB, Edge SB, et al. Breast cancer. Clinical practice guidelines in oncology. J Natl Compr Canc Netw. 2009 Feb;7(2):122-92.
Chlebowski RT, Kuller LH, Prentice RL, Stefanick ML, Manson JE, Gass M, et al. Breast cancer after use of estrogen plus progestin in postmenopausal women. N Engl J Med. 2009 Feb 5;360(6):573-87.
Hayes DF. Clinical practice. Follow-up of patients with early breast cancer. N Engl J Med. 2007;356(24): 2505-13.
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