ABSTRACT

Invasive lobular carcinoma (ILC) of the breast makes up 5 to 15 percent of all invasive breast cancers. It has distinctive clinical and histopathological features when compared to invasive ductal carcinoma (IDC). This study intends to describe factors influencing sentinel lymph node (SLN) positivity in patients with “pure” ILC.

Data of 105 patients, who were treated at a tertiary oncology center, with lobular carcinoma of the breast that were subjected to SLN biopsy was probed retrospectively. Patients were categorized as ≤60 and >60 years of age, positive or negative for estrogen receptor and progesterone, tumor grade I, II and III, Ki67≤15% and >30%, lymphovascular invasion presence and the presence of multicentricity and multifocality.

Mean age at the time of diagnosis was 52 (38-81). Mean tumor size was 2.7 cm (0.7-13cm). Univariate analyses revealed a significant relationship between tumor size (≤2 cm vs >2cm) and metastasis in the SLN. This relation kept its significance in multivariate analyses. (p=0.013).

With so many different characteristics from IDC, ILC is mostly a uniform tumor. In this study, tumor size was the only independent clinical parameter that was found related to SLN metastases.