Invasive Lobular Cancer (ILC)
What Is Invasive Lobular Breast Cancer?
Invasive lobular breast cancer (ILC) is invasive breast cancer that begins in the lobules (milk glands) of the breast and spreads to surrounding normal tissue. It can also spread through the blood and lymph systems to other parts of the body.
Invasive lobular breast cancer is the second most common type of breast cancer. Over 10% of invasive breast cancers are invasive lobular carcinomas.
Though mammograms are helpful and important, they are less likely to detect invasive lobular breast cancer than other types of breast cancers. Invasive lobular cancer doesn’t always appear clearly on a mammogram, instead an MRI might be needed.
What Is The Difference Between Invasive Lobular Carcinoma (ILC) and Lobular Carcinoma In Situ (LCIS)?
Lobular carcinoma in situ (LCIS) is not breast cancer; it is a condition where abnormal cells are found in the milk glands, or lobules, of the breast and have not invaded any other area. Invasive lobular carcinoma (ILC) is cancer that began growing in the lobules (milk glands) of the breast and is invading the surrounding tissue. Cancer staging done by a physician, along with a physical exam and medical history can help identify the best treatment options.
Over 80% of the time, invasive lobular carcinoma (ILC) is ER+ and HER2-. Sometimes invasive lobular breast cancer can be larger than it appears to be when reviewing a mammogram because of the way it grows. It can be commonly identified as a higher stage cancer.
Invasive lobular carcinoma is known for being a slow growing tumor, usually grade I or II. Slow growing, grade I tumors don’t usually respond well to chemotherapy, so hormonal therapy is key for this type of cancer.
If it spreads to other organs, becoming Stage IV breast cancer, it typically goes to the colon, uterus, ovary, stomach, lung, bone, and other areas.
Medically reviewed June 2023
Materials on this page courtesy of National Cancer Institute