Lobular Carcinoma In Situ

Lobular Carcinoma in situ originates in the lobules of the breast, which are the glands that produce breast milk for the ducts to carry to the nipple. LCIS occurs when abnormal cells that resemble cancer begin growing in the epithelial tissue (tissue that line the lobules) of the breast. Because these cells have not invaded the walls of the lobules, and do not typically spread beyond the lobules, LCIS is not considered cancer. However, those with LCIS have a 7 to 12 times higher risk of developing an invasive cancer (LCIS or DCIS) in either breast later on, and therefore active surveillance, preventive therapy, or even surgery may be necessary. LCIS is sneaky. It often does not show up on mammograms, and is usually diagnosed through a lump in the breast or through a breast biopsy that is conducted for another reason.

Types of Lobular Carcinoma In Situ

Classic LCIS: the abnormal cells lining the lobules are slightly smaller than normal/healthy cells, but still resemble them.

Pleomorphic LCIS: the abnormal cells lining the lobules are larger than regular cells and the difference is more noticeable.

Florid LCIS: The abnormal cells lining the lobules have grown into a mass, typically with an area of dead cells in the middle.

The most common ways to treat/manage LCIS are:

Active Surveillance
Your doctor may recommend more frequent exams to monitor for breast cancer. Yearly mammograms may be recommended, but since LCIS is hard to detect, your doctor may recommend monthly self breast exams and more frequent clinical breast exams. Periodic MRI's (breast magnetic resonance imaging) may also be recommended, especially if you have a family history of breast cancer or a BCRA 1/2 mutation, both of which put you at higher risk of cancer.

Preventive Therapy:
Preventative therapy is a treatment that is intended to prevent cancer before it develops. The two most common types of preventative therapies are selective estrogen receptor antagonists (SERMS)- such as tamoxifen for premenopausal women or raloxifene for post menopausal women- or aromatase inhibitors such as exemestane or letrozole.
To learn more about these preventative hormone therapies, click here.

Surgery:
If your LCIS is Pleomorphic (the cells growing in the lobules look larger or more abnormal that traditional LCIS cells) or Florid (the cells have grown in a large enough group to form a mass), your doctor may recommend surgery, such as a lumpectomy or mastectomy.
To learn more about surgery, click here.

American Cancer Society. (2022). Lobular Carcinoma In Situ . Retrieved from: https://www.cancer.org/cancer/types/breast-cancer/non-cancerous-breast-conditions/lobular-carcinoma-in-situ.html
Mayo Clinic. (2022). Lobular Carcinoma In Situ (LCIS). Retrieved from: https://www.mayoclinic.org/diseases-conditions/lobular-carcinoma-in-situ/diagnosis-treatment/drc-20374535