Biological and clinical characteristics of invasive ductal carcinoma with lobular pattern

Abstract

Introduction: Invasive Breast Cancer (IBC) has a great epidemiological impact in our society; it is the first most frequent cancer among women and the first cause of death from cancer in women worldwide. Invasive ductal carcinoma (IDC) represents the largest group of malignant tumours of the breast, comprising up to 75% of the cases. It is a heterogeneous entity with no clear definition and its diagnosis is made by the exclusion of other special types of Breast Cancer. Women presenting with Invasive Ductal Carcinoma have a wide range of prognostic outcomes, thus, there is a need to reassess tumours classified as Invasive Ductal Carcinomas in an effort to elaborate more accurate subclassifications of this heterogeneous entity. It is in this context that, in the pathology unit of Josep Trueta Hospital of Girona, a possible morphological variant of Invasive Ductal Carcinoma has been recognized. It could be described as an Invasive Ductal Carcinoma exhibiting a growth pattern in linear cords, typically seen in Invasive Lobular Carcinoma, yet not fulfilling the criteria to be classified as mixed tumours. To our knowledge, these tumours have not been assessed in past studies. Objective: To assess the clinicopathological characteristics of Invasive Ductal Carcinoma with Lobular Pattern (IDCLp) regarding, age of presentation, nationality, menopausal status, family history, primary tumour size, histological tumour type, histological grade, lymph node status, bilateralism, oestrogen and progesterone receptors, HER2 overexpression, staging and treatment procedures, disease-free survival and survival time, and to determine whether these characteristics significantly differ from the classic types of Invasive Ductal Carcinoma and Invasive Lobular Carcinoma (ILC). Methods: This is a retrospective, observational and analytical study. Information will be reviewed and collected from the Cancer Registry of Girona database which contains epidemiologic information of all Breast Cancer cases of the province of Girona since 1994. Three cohorts will be analysed retrospectively, between 1994 and 2016, regarding their clinicopathological characteristics: Invasive Ductal Carcinoma with Lobular Pattern cases, Invasive Ductal Carcinoma, and Invasive Lobular Carcinoma