Invasive Lobular Carcinoma

Lobular breast cancer (also called invasive lobular carcinoma, or ILC) is breast cancer that starts in the milk-producing gland, or lobules, of your breast and has spread into surrounding breast tissue. It accounts for about 10% to 15% of all breast cancers and is the second most common type of breast cancer. Left untreated, lobular breast cancer spreads to nearby lymph nodes, and then to other areas of your body.

What’s the difference between invasive lobular breast cancer and invasive ductal carcinoma?

Invasive lobular breast cancer tends to grow in a single-file pattern of cells. Invasive ductal carcinoma typically forms a mass or lump.

Who’s affected by lobular breast cancer?

Women and people assigned female at birth (AFAB) who are age 55 and older are most likely to develop invasive lobular carcinoma. Men and people who are assigned male at birth can develop ILC, too, though it’s rare. Transwomen have a higher risk of developing breast cancer than cisgender men. Conversely, transmen have a lower risk compared to cisgender women.

Unlike invasive ductal carcinoma (IDC), invasive lobular carcinoma usually occurs later in life. Many people are in their early 60s at the time of their diagnosis.