CausesBy Mayo Clinic staff
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 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 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.
- Abeloff MD, et al. Cancer of the breast. In: Abeloff MD, et al. Abeloff's Clinical Oncology. 4th ed. Philadelphia, Pa.: Churchill Livingstone Elsevier; 2008:1875.
- Breast cancer. Fort Washington, Pa.: National Comprehensive Cancer Network. http://www.nccn.org/professionals/physician_gls/PDF/breast.pdf. Accessed April 15, 2011.
- Sabel MS. Lobular carcinoma in situ of the breast. http://www.uptodate.com/home/index.html. Accessed April 26, 2011.
- Venkitaraman R. Lobular neoplasia of the breast. The Breast Journal. 2010;16:519.
- Arpino G ,et al. Premalignant and in situ breast disease: Biology and clinical implications. Annals of Internal Medicine. 2005;143:446.
- SEER stat fact sheet: Breast. National Cancer Institute. http://seer.cancer.gov/statfacts/html/breast.html. Accessed May 4, 2011.