Synchronous lobular carcinoma in situ and invasive lobular cancer: Marker or precursor for invasive lobular carcinoma

Aim: Lobular carcinoma in situ (LCIS) is a known risk factor for invasive breast carcinoma, but there is increasing data indicating a possible precursor relationship This study investigates the incidence of lobular carcinoma in situ that occurs with invasive lobular carcinoma (ILC). Methods: Women diagnosed with MC or LCIS from 2000 to 2010 were retrospectively identified and reviewed after institutional review board approval. This group was divided into two cohorts: ILC alone, and LCIS and ILC (ILC/LCIS). Patient demographics, disease characteristics, and treatment modalities were captured. p < 0.05 is considered significant. Results: A total of 148 patients with ILC or LCIS were identified. Forty-four (54%) patients with only ILC, and 37 (46%) patients with ILC/LCIS were identified. Median age at diagnosis was 62 for ILC and 64 years for ILC/LCIS (p = 0.8). In patients with ILC, total mastectomy was the predominant treatment modality in 28 of 44 (64%) patients, while 18 of 37 (49%) patients with ILC/LCIS underwent breast conservation therapy (p = 0.3). Median largest tumor diameter was 35 mm (range 1-110) for ILC, and 15 mm (range 5-85) for ILC/LCIS (p = 0.03). Nodal status was positive in 17 of 39 (44%) ILC and 13 of 34 (38%) ILC/LCIS (p = 0.6). Conclusions: The 46% incidence of LCIS associated with ILC in our cohort study is similar to that reported for ductal carcinoma in situ identified with invasive ductal carcinoma at similar to 40%. The association of pre-invasive and invasive lobular lesions should be further studied in a large scale prospective study to assess for a precursor relationship. (C) 2014 Elsevier Ltd. All rights reserved.