Distinct clinical and prognostic features of infiltrating lobular carcinoma of the breast: Combined results of 15 International Breast Cancer Study Group clinical trials

Abstract

Purpose: To determine how patients with infiltrating lobular carcinoma (ILC) differ from patients with the more common infiltrating ductal carcinoma (IDC) with regard to patient and tumor factors, local treatment, and patterns of recurrence. Patients and Methods: Twelve thousand two hundred six breast cancer patients entered onto 15 International Breast Cancer Study Group trials between 1978 and 2002 were categorized as having ILC, IDC, or other/mixed types. Results: Seven hundred sixty-seven tumors (6.2%) were classified as ILC, 8,607 (70.5%) were classified as IDC, and 2,832 (23.2%) were classified as other. The analysis is limited to the 9,374 patients categorized as either pure IDC or IL..