Invasive lobular carcinoma of the breast: clinicopathological features and patient outcomes

Aim: The incidence of invasive lobular carcinoma (ILC), a breast cancer type comprising several variants with distinct morphological and molecular features and clinical behaviors, has been increasing in recent years. Unlike the well-defined classical lobular carcinoma, the most common ILC variant, some uncertainties remain regarding the features of other ILC variants. Therefore, we investigated the clinicopathological features and survival outcomes of specific ILC variants. MATERIAL AND METHODS: This retrospective study compared the tumor and patient characteristics and outcomes according to specific ILC variants in 77 patients who underwent surgery for ILC between January 2010 and December 2016 at a single center in Turkey. RESULTS: The mean patient age was 54.58 +/- 11.7 years. The ILC variants were classical, pleomorphic, tubulolobular, solid, and signet ring cell in 49(63.6%), 14(18.2%), 10(12.8%), 2(2.7%), and 2(2.7%) patients, respectively. The mean tumor diameter, histological grade, Ki-67 proliferation index, nodal metastasis, E-cadherin expression, lymphovascular invasion, and type of surgery were significantly different among the variants. However, there were no significant differences in the rates of local recurrence, distant metastasis, and overall survival among the variants. CONCLUSIONS: Despite the good prognostic characteristics and good response to treatment, several studies have reported that ILC is associated with poor long-term outcomes. Therefore, significant challenges remain in the management of ILC. Although it is believed to be a specific histological type, ILC is clinically and pathologically heterogenous. Therefore, the identification of patients with poor prognostic variants should aid in the implementation of efficient and personalized treatment options.