Distinguishing Between Invasive Ductal and Lobular Carcinoma

Of the two most common histologic subtypes of invasive breast cancer, infiltrating ductal carcinoma (IDC) occurs in 70% to 75% of patients and infiltrating lobular carcinoma (ILC) occurs in only 6% to 9% of patients. Given this uneven distribution, conclusions about treatment have been driven largely by outcomes for patients with IDC. Several reports have identified important differences between ILC and IDC (e.g., diagnostic challenges, surgical considerations, biologic features, and prognoses); however, certain distinctions between the two subtypes remain unclear.

To elucidate further the differences between ILC and IDC, researchers examined records of 9374 patients with either subtype who were enrolled in 15 adjuvant-therapy trials within …