Date of Award

January 2017

Document Type

Thesis

Degree Name

Medical Doctor (MD)

Department

Medicine

First Advisor

Marcella Nunez-Smith

Abstract

Trinidad and Tobago (T&T) is a Caribbean island with a population of approximately 1.3 million. T&T has one of the highest breast cancer mortality rates in the region. Notably, a large proportion of breast cancer cases in T&T appear to occur at a young age, as nearly 36% of breast cancers are diagnosed under the age of 50. It is known that a younger age at diagnosis can be associated with Hereditary Breast and Ovarian Cancer syndrome (HBOC). However, the prevalence of HBOC mutations remains unknown in T&T, as accessible health services for genetic counseling and testing in T&T currently are limited. As such, our study aimed to determine the prevalence and spectrum of HBOC mutations among women with breast cancer in T&T who met National Comprehensive Cancer Network (NCCN) criteria for evaluation for HBOC syndrome to determine the need to include genetic counseling and testing in local oncology management in T&T.

At the main oncology unit in T&T, female breast cancer patients who met the NCCN criteria were recruited for this study. We conducted interviews inquiring about their personal breast cancer diagnosis, as well as any relevant family history. This was followed by the collection of saliva samples using Oragene kits, which were then analyzed by Color Genomics Inc. for 30 genes associated with hereditary cancers. Finalized results were returned to patients by genetic counselors from Color Genomics. In total, 58 patients who met NCCN guidelines were sequenced and results were returned. They showed that of 58 samples, 15 patients tested positive for deleterious HBOC germline mutations: 9 - BRCA1, 3 - BRCA2, 1 – CHEK2, 1- PALB2 and 1 – PTEN, with an overall prevalence rate of 25.8%. This prevalence rate is remarkable, given that HBOC mutations among U.S. women with breast cancer are found in only 5-10% of patients. These initial results clearly demonstrate the need to include genetic counseling and testing in the local oncology management in T&T, as the identification of HBOC mutations can influence treatment options, as well as help identify family members who are at high risk for cancer predisposition. Ultimately, this implementation could help alleviate the country’s high incidence and mortality rates with respect to breast cancer.

Comments

This thesis is restricted to Yale network users only. It will be made publicly available on 06/12/2019

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