Lobular and Ductal Breast Cancer: How Do They Differ?

Invasive lobular carcinoma (ILC) is the second most common histologic subtype of breast cancer, after invasive ductal carcinoma (IDC), accounting for 5%–15% of all breast cancers. Several key clinical characteristics have long been appreciated to distinguish ILC from IDC, such as less-clear mammographic visualization and unusual metastatic sites, including serosal surfaces in the abdomen and pelvis.

To better differentiate the clinicopathologic features and outcomes between ILC and IDC, investigators conducted a retrospective cohort study of 3617 ILC patients and 30,045 IDC patients diagnosed between 1990 and 2017 at three large U.S. cancer centers.

Key findings were as follows:

• Compared with IDC patients, ILC patients were more likely to be o…