Investigation of triple negative breast cancer rates in women diagnosed with breast cancer in Trinidad and Tobago.

Abstract

e19005 Background: According to the WHO/PAHO, Trinidad and Tobago (T&T) has the 2nd highest breast cancer mortality rate in the Caribbean region. In T&T, citizens of African descent make up about 36.8% of the T&T population, with 24.8% being of East Indian ancestry, and 32.4% identifying as having mixed heritage. In the United States, it has been showed that African American women, despite being diagnosed less often, have an earlier onset of breast cancer with less favorable clinical outcomes. One of the factors studied has been the higher frequency of triple negative breast cancer (TNBC) in African American women particularly when these patients are diagnosed at a younger age. Notably, a large proportion of breast cancer cases in T&T appear to occur at a young age, with nearly 36% of them being diagnosed under the age of 50. However, breast cancer tumor phenotypes have not been well studied. Therefore, we sought to investigate the distribution of tumor hormone receptor markers in the T&T breast cancer population. Methods: At the National Radiotherapy Center, T&T’s main oncology unit, we investigated breast cancer patients born in T&T using paper chart reviews. We collected information about their demographics, personal breast cancer diagnosis, tumor hormone receptor status and germline genetic testing results. Results: So far, we reviewed 90 patient charts, and in our sample, 33.3% (30/90) had TNBC. This is higher than the rates in the US where TNBC accounts for 10-20% of breast cancer patients, and of those TNBC cases, 10.6% have BRCA 1 or BRCA 2 mutations. In our T&T sample, of those with TNBC, 23.3% (7/30) had a HBOC mutation (5 BRCA, 1 TP53 and 1 PTEN). Average diagnosis age of TNBC cases reported in our sample was 45.7 years. In our sample, 52.2% (47/90) identified as having African ancestry, 37.8% (34/90) identified as having East Indian ancestry and 10% (9/90) identified as Mixed. Of the patients with TNBC, 63.3% (19/30) were of African ancestry, 30.0% (9/30) were of East Indian ancestry and 6.7% (2/30) identified as Mixed. Conclusions: Therefore, our sample results suggest that there is a significant portion of the breast cancer cases being TNBC in the T&T population, particularly in citizens with African ancestry. As we continue to finalize the incoming data, we hope to draw associations between tumor pathology, clinical presentation and genetic profiles. However, these initial results demonstrate the need to study tumor pathology within the T&T population, as this could lead to improved clinical and screening guidelines specific to T&T citizens.