It's not clear what causes LCIS. LCIS begins when cells in a milk-producing gland (lobule) of a breast develop genetic mutations that cause the cells to appear abnormal. The abnormal cells remain in the lobule and don't extend into, or invade, nearby breast tissue.
LCIS isn't cancer and it doesn't develop into cancer. But having LCIS increases your risk of breast cancer and makes it more likely that you could develop invasive breast cancer.
The risk of breast cancer in women diagnosed with LCIS is thought to be approximately 20 percent. Put another way, for every 100 women diagnosed with LCIS, 20 will be diagnosed with breast cancer and 80 won't be diagnosed with breast cancer. The risk of developing breast cancer for women in general is thought to be 12 percent. Put another way, for every 100 women in the general population, 12 will be diagnosed with breast cancer in their lifetime.
Your individual risk of breast cancer is based on many factors. Talk to your doctor to better understand your personal risk of breast cancer.
Aug. 15, 2014
- Niederhuber JE, et al., eds. Abeloff's Clinical Oncology. 5th ed. Philadelphia, Pa.: Churchill Livingstone Elsevier; 2014. http://www.clinicalkey.com. Accessed Feb. 17, 2014.
- Breast cancer. Fort Washington, Pa.: National Comprehensive Cancer Network. http://www.nccn.org/professionals/physician_gls/f_guidelines.asp. Accessed Feb. 17, 2014.
- Sabel MS. Atypia and lobular carcinoma in situ: High risk lesions of the breast. http://www.uptodate.com/home. Accessed March 12, 2014.
- Cameron JL, et al., eds. Current Surgical Therapy. 11th ed. Philadelphia, Pa.: Saunders Elsevier; 2014. http://www.clinicalkey.com. Accessed Feb. 17, 2014.
- Chen WY. Selective estrogen receptor modulators and aromatase inhibitors for breast cancer prevention. http://www.uptodate.com/home. Accessed March 12, 2014.
- SEER stat fact sheet: Breast cancer. National Cancer Institute. http://seer.cancer.gov/statfacts/html/breast.html. Accessed March 12, 2014.
- Moyer VA. Medications for risk reduction of primary breast cancer in women: U.S. Preventive Services Task Force recommendation statement. Annals of Internal Medicine. Sept. 24, 2013. http://annals.org/article.aspx?articleid=1740758. Accessed March 12, 2014.
- Visvanathan K, et al. Use of pharmacologic interventions for breast cancer risk reduction: American Society of Clinical Oncology clinical practice guideline. Journal of Clinical Oncology. 2013;31:2942.
- Degnim AC, et al. Surgical management of high-risk breast lesions. Surgical Clinics of North America. 2013;93:329.
- Townsend CM Jr, et al. Sabiston Textbook of Surgery: The Biological Basis of Modern Surgical Practice. 19th ed. Philadelphia, Pa.: Saunders Elsevier; 2012. http://www.clinicalkey.com. Accessed Feb. 17, 2014.
- Pruthi S (expert opinion). Mayo Clinic, Rochester, Minn. March 16, 2014.
- Vogel VG, et al. Effects of tamoxifen vs raloxifene on the risk of developing invasive breast cancer and other disease outcomes: The NSABP study of tamoxifen and raloxifene (STAR) P-2 trial. JAMA. 2006;295:2727.
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