A Comparison of the Clinicopathological Features, Metastasis Sites and Survival Outcomes of Invasive Lobular, Invasive Ductal and Mixed Invasive Ductal and Lobular Breast Carcinoma

Abstract

Objective: We compared the breast cancer patients with invasive lobular carcinoma (ILC), invasive ductal carcinoma (IDC) and mixed invasive ductaland lobular carcinoma (IDLC) in terms of clinicopathological and treatment features, metastatic patterns and long-term survival.Materials and Methods: In a 10 years patient cohort, 3412 patients with unilateral breast carcinoma were enrolled in the study. Tumors were classifiedhistologically according to criteria described by World Health Organization classification.Results: The highest rate of T3 tumors were found in IDLC patients, the lowest in IDC patients, and the difference between groups was significant onlyin comparison of IDC vs IDLC. Axillary positivity rate was highest in IDLC, lowest in ILC; differences were significant in comparisons of IDLC vs ILCand IDLC vs IDC. There was no significant difference between the patient groups in terms of surgical treatment, mastectomy and breast conservingsurgery. Rate of bone metastasis was highest in IDLC, lowest in IDC, with significant difference between IDLC and IDC. Locoregional recurrence-freesurvival (LRFS) rate was 90.9% in ILC patients, 92.5% in IDC patients, 92.9% in IDLC patients, with no significant difference between the groups;in multivariate Cox analysis, histological type had no prognostic significance (p=0.599). Distant metastasis-free survival (DMFS) rate was 66.2% in ILCpatients, 66.7% in IDC patients, 57.1% in IDLC patients; in multivariate Cox analysis, histological type had no prognostic significance (p=0.392).Conclusion: Although these results suggest that IDLC may have a worse prognosis than IDC and ILC, in multivariate analysis LRFS and DMFS werenot significantly different among the histological type groups.