A retrospective analysis of breast cancer subtype based on ER/PR and HER2 status in Ghanaian patients at the Korle Bu Teaching Hospital, Ghana.

Background: Breast cancer is a heterogeneous disease composed of multiple subgroups with different molecular alterations, cellular composition, clinical behaviour, and response to treatment. This study evaluates the occurrence of the various subtypes and their clinical and pathological behaviour in the Ghanaian breast cancer population at the Korle Bu Teaching Hospital (KBTH).

Methods: Retrospective review of case notes of patients who had completed treatment for breast cancer at the KBTH within the last 5 years was conducted between April 2011 and March 2012. Subtypes were determined by immunohistochemistry classification based on expression of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor-2 (HER-2).

Result: A total of 165 cases contributed to this study. The mean age at diagnosis was 52.5 ± 12.1 years. Tumour size ranged from 0.8 cm to 15 cm with a mean of 4.9 ± 2.8 cm and median of 4 cm. Tumour grade was Grade I 8.3 %, Grade II 60.8 % and Grade III 30.8 %. ER, PR and HER2/neu receptor positivity was 32.1, 25.6 and 25.5 % respectively. Almost half (49.4 %) of the study population had triple negative tumours. Luminal A, luminal B and non-luminal HER2 were 25.6, 12.2, and 12.8 % respectively. No statistically significant association was seen between subtype and tumour size, tumour grade, lymph node status and age at diagnosis.

Conclusion: Triple negative tumour is the most occurring subtype in the Ghanaian breast cancer population treated at the Korle Bu Teaching Hospital. Lack of association seen between subtypes and their clinical and pathological behaviour could be due to small sample size.