Triple negative breast cancer in people of North East India: critical insights gained at a regional cancer centre.

Background: Breast cancer is a heterogeneous disease comprising of distinct biological subtypes with many targeted prognostic biomarkers having therapeutic implications. However, no specific targeted therapy for triple negative breast cancer has been discovered to date and hence further research is needed. Aim: The aim and objectives of the present study were to examine the prevalence of triple negative breast cancer (TNBC) in North-East India and to compare the clinicopathological parameters in two study groups defined by immunohistochemistry (IHC) –“TNBC” and “Others”. Materials and Methods: We carried out a retrospective study in a cohort of 972 patients diagnosed with invasive breast carcinoma in the Department of Pathology, Dr. B. Borooah Cancer Institute, a Regional Cancer Centre for treatment and research, Guwahati, for a period of 3 years and 10 months from January 2010 to October 2013. Based on IHC findings, patients were divided into two groups - “TNBC” and “Others”. All relevant clinicopathological parameters were compared in both. TNBC were defined as those that were estrogen receptor (ER), progesterone receptor (PR), and HER2/neu negative while those positive for any of these markers were defined as “Others”. Results: In this study, out of total 972 cases 31.9% (310 cases) were defined as TNBC and 662 cases (68.1%) as “Others” based on IHC markers. Compared to the “Others” category, TNBC presented at an early age (mean 40 years), were associated with high grade large tumours and high rate of node positivity, IDC NOS being the most common histological subtype in TNBC. Conclusions: TNBC accounts for a significant portion of breast cancers in this part of India and commonly present at younger age and tend to be large high grade tumours.