Clinical and pathological features of triple negative breast carcinoma

A research report submitted to the Faculty of Health Sciences, University of the Witwatersrand, in partial fulfilment of the degree of Masters of Medicine in Anatomical Pathology Johannesburg, 2016BACKGROUND: Breast carcinoma is the most common carcinoma diagnosed in females worldwide. The mortality rate from breast carcinoma has declined over the last three decades. Receptor negative tumours, perhaps due to limited treatment options, have a higher mortality rate. OBJECTIVES: The aim of this study is to determine patient demographics and tumour characteristics of triple negative breast carcinoma (TNBC) at the histopathology department of Charlotte Maxeke Johannesburg Academic Hospital (CMJAH). METHOD: An observational, cross-sectional, retrospective study design was used. A search of our electronic database identified 1126 individuals with invasive breast carcinoma between 1 January 2011 and 31 December 2012. Tumour characteristics and patient demographics were subsequently assessed on those individuals with confirmed TNBC. RESULTS: 13.0% of tumours had a triple negative phenotype. Individuals with TNBC ranged from 28.0 to 89.0 years with a median age of 44.0 years; the mean age was 55.4 years (SD ± 13.4 years). TNBCs were ~70 times more common in females than males. The tumours ranged in size from 6.0 mm to 160.0 mm, with a median size of 36.0 mm; the mean tumour size was 48.3 mm (SD ± 33.1 mm). The majority of tumours (90.8%) were invasive carcinomas of no special type. 67.9% of individuals presented with high grade tumours and the majority presented with stage II or III disease (43.8% and 45.6% respectively). v Concurrent in-situ malignancy was identified in 34.1% of cases. 69.6% of individuals presented with nodal involvement. Unifocal disease was considerably more common than multifocal disease (90.7% compared to 9.3%). The distribution of left and right sided disease was similar (54.5% and 43.2% respectively) and bilateral disease was uncommon (2.3%). CONCLUSION: TNBCs comprise 13.0% of breast carcinomas, this is lower than the prevalence in Soweto and other African countries. Differences in racial and socioeconomic demographics may provide an explanation. Patient demographics and tumour characteristics of TNBCs in our population are largely similar to the data available in the literature. The substantial size and stage difference amongst studies suggests that factors other than the triple negative phenotype could contribute to large tumour size and advanced stage at presentation. In the South African context, barriers to accessing healthcare provide a plausible explanation.MT201