Abstract P3-10-01: Investigation of HBOC germline mutations in women diagnosed with breast cancer in Trinidad and Tobago
Authors: Parkinson GT , Chagpar AB , Hofstatter EW , Nunez-Smith M 
Published: March 2017

Background: Trinidad and Tobago (T&T) is a southern Caribbean island with a population of approx. 1.3 million. According to WHO/PAHO, T&T has the 2nd highest breast cancer mortality rate in the region, and breast cancer continues to lead in incidence and mortality in cancers among female citizens. Notably, a large proportion of breast cancer cases in T&T appear to occur at a young age; with nearly 36% of breast cancers 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), characterized by germline mutations in tumor suppressor genes such as BRCA, PTEN and TP53. Yet, the prevalence of HBOC mutations remains unknown in T&T, as local health services for genetic counseling and testing in T&T currently do not exist. As such, our study aimed to determine the prevalence rate of HBOC mutations among women with breast cancer in T&T who met NCCN criteria for evaluation for HBOC syndrome; thus investigating whether there is a need to include genetic testing and counseling in local oncology management in T&T.

Methods: At the National Radiotherapy Center, the main oncology unit in T&T, female breast cancer patients, who met the NCCN criteria for further genetic counseling/testing, were recruited either through doctor referrals or chart reviews. We conducted interviews inquiring about their personal breast cancer diagnosis, risk factors for breast cancer, 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; including 19 HBOC associated genes such as BRCA1, BRCA2, TP53 and PTEN. Finalized results were returned to patients by genetic counselors from Color Genomics.

Results: 165 patients who met NCCN guidelines for HBOC counseling/testing were approached, of whom 150 agreed to participate. Due to funding and resource limitations, 60 samples were collected thus far; ages ranged from 19-56. The majority of women met NCCN criteria based on age of personal breast cancer diagnosis (40%), and/or family history of breast and/or ovarian cancer (60%). Preliminary results show that of 49 samples, 10 patients tested positive for deleterious HBOC germline mutations: 7 - BRCA1, 2 - BRCA2 and 1 - PTEN; thus far giving a prevalence rate of 20%.

Discussion: Therefore, our results found a strikingly high HBOC germline mutation prevalence rate of 20% among a cohort of female breast cancer patients meeting NCCN criteria in T&T. As we continue to finalize the incoming data on these patients, we hope to draw associations between their genetic status and their respective tumor markers, family history, and personal medical history. However, these initial results 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 integration could help alleviate the country's high incidence and mortality rates with respect to breast cancer, and save the public healthcare system significant financial resources.Background: Trinidad and Tobago (T&T) is a southern Caribbean island with a population of approx. 1.3 million. According to WHO/PAHO, T&T has the 2nd highest breast cancer mortality rate in the region, and breast cancer continues to lead in incidence and mortality in cancers among female citizens. Notably, a large proportion of breast cancer cases in T&T appear to occur at a young age; with nearly 36% of breast cancers 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), characterized by germline mutations in tumor suppressor genes such as BRCA, PTEN and TP53. Yet, the prevalence of HBOC mutations remains unknown in T&T, as local health services for genetic counseling and testing in T&T currently do not exist. As such, our study aimed to determine the prevalence rate of HBOC mutations among women with breast cancer in T&T who met NCCN criteria for evaluation for HBOC syndrome; thus investigating whether there is a need to include genetic testing and counseling in local oncology management in T&T.

Methods: At the National Radiotherapy Center, the main oncology unit in T&T, female breast cancer patients, who met the NCCN criteria for further genetic counseling/testing, were recruited either through doctor referrals or chart reviews. We conducted interviews inquiring about their personal breast cancer diagnosis, risk factors for breast cancer, 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; including 19 HBOC associated genes such as BRCA1, BRCA2, TP53 and PTEN. Finalized results were returned to patients by genetic counselors from Color Genomics.

Results: 165 patients who met NCCN guidelines for HBOC counseling/testing were approached, of whom 150 agreed to participate. Due to funding and resource limitations, 60 samples were collected thus far; ages ranged from 19-56. The majority of women met NCCN criteria based on age of personal breast cancer diagnosis (40%), and/or family history of breast and/or ovarian cancer (60%). Preliminary results show that of 49 samples, 10 patients tested positive for deleterious HBOC germline mutations: 7 - BRCA1, 2 - BRCA2 and 1 - PTEN; thus far giving a prevalence rate of 20%.

Discussion: Therefore, our results found a strikingly high HBOC germline mutation prevalence rate of 20% among a cohort of female breast cancer patients meeting NCCN criteria in T&T. As we continue to finalize the incoming data on these patients, we hope to draw associations between their genetic status and their respective tumor markers, family history, and personal medical history. However, these initial results 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 integration could help alleviate the country's high incidence and mortality rates with respect to breast cancer, and save the public healthcare system significant financial resources.

Citation Format: Parkinson GT, Chagpar AB, Hofstatter EW, Nunez-Smith M. Investigation of HBOC germline mutations in women diagnosed with breast cancer in Trinidad and Tobago [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P3-10-01.