Invasive Lobular Carcinoma: Imaging Characteristics, Size at Presentation and Bilaterality.

Abstract

Abstract Aims: Invasive Lobular Carcinoma (ILC) is often described as elusive to standard imaging modalities and usually requiring mastectomy to obtain clear margins. Its reputation of being bilateral has been disputed by most recent studies. The aim of this study is to investigate whether the radiological diagnosis of ILC at first symptomatic presentation is more difficult than that of Invasive Ductal Carcinoma (IDC) in a modern breast clinic; also whether its size, surgical treatment at presentation and bilaterality is different from IDC and its subtypes.Materials & Methods: The radiological codes given to all new symptomatic patients with invasive breast cancer, presenting at the breast clinic of St Mary's Hospital and undergoing surgery as first treatment, (n=754), were collected prospectively between 1998 and 2005 and final mastectomy rates were also recorded. Histological reports of all synchronous and metachronous bilateral cancers presenting with at least one tumour between 1998 and 2007 were analyzed (n=65).Results: ILC was given suspicious radiological codes as often as IDC (90% vs 93%). On final histology, ILC measured on average 3.6cm compared to 2.5cm for IDC (p<0.05). There was a trend of ILC requiring mastectomy more often (51% vs 43%). 12.7% of patients with at least one ILC diagnosis have developed bilateral breast cancer compared to 4.5% of patients who have never had an ILC diagnosis (p<0.05).Results IDCILCMixedSpecialUnknownTotalNo of patients551 (73%)86 (11%)52 (7%)62 (8%)3 (0.4%)754Age (mean)5861596157.659Mastectomy191 (43%)36 (51%)23 (49%)13 (25%) 263Breast conservation257 (58%)36 (51%)24 (51%)41 (77%) 358Size cm (mean)2.53.62.52.0-2.7USS suspicious473 (93%)72 (90%)41 (90%)42 (76%)2 (100%)630MMG suspicious412 (81%)58 (73%)39 (80%)43 (80&)2 (100%)554 Conclusions: ILC is as easy to diagnose radiologically as IDC in symptomatic breast patients. However, ILC is larger at first presentation. In our database, ILC identified a subgroup of breast cancer patients who have a 3-fold higher risk of developing bilateral breast cancer of various histological types. Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 4015.