Sentinel Lymph Node Metastasis in Invasive Lobular Carcinoma of the Breast.

Objective: 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. Materials and Methods: 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. Results: 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). Conclusion: 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.

Factors Influencing Non-sentinel Node Metastasis in Patients with Macrometastatic Sentinel Lymph Node Involvement and Validation of Three Commonly Used Nomograms.

OBJECTIVE: Omitting axillary lymph node dissection (ALND) in a subgroup of patients with sentinel lymph node (SLN) metastasis is becoming a widely accepted practice. Avoiding the well-known complications of ALND is the sole aim without compromising the curative intention of surgery. MATERIALS AND METHODS: The data were probed for breast cancer patients that were operated on between February 2014 and June 2016. SLN biopsies were performed in 507 patients and out of 157 patients who underwent ALND for a metastatic SLN, 151 were found eligible for the analyses as having macrometastatic (>2mm) SLN. MD Anderson, Memorial Sloan Kettering Cancer Center and Helsinki nomograms were also tested in our patient population. RESULTS: Pathologic tumor size greater than 2 cm, the ratio of metastatic SLN to dissected SLN, metastatic tumor greater than 1 cm and tumors that extended outside the SLN's capsule were found to be associated with non-sentinel node metastasis in both univariate and multivariate tests. MD Anderson nomogram performed well with an area under the curve (AUC) value of 0.72. CONCLUSION: Our results suggest that ALND should be considered in patients with macrometastatic SLN greater than 10 mm in size, have extracapsular extension, have metastatic SLNs at a rate of more than 50% and whose primary tumor is greater than 2 cm.