Abstract P5-09-17: Risk reducing interventions among BRCA 1 and 2 female carriers in Newfoundland and Labrador: A provincial analysis
Authors: Seal MD , Roebothan A , Gabriel A , Dawson L 
Published: May 2019

Introduction

Germline mutations in the tumour suppressor genes BRCA 1 and 2 result in a significant increase in cancer predisposition. Female carriers can have up to a 50-70% chance of developing a breast malignancy in their life time and a risk of 20-40% for ovarian cancer. Management options for women with a BRCA mutation include screening with annual mammography and magnetic resonance imaging (MRI), prophylactic surgery and chemoprevention. There is substantial evidence that preventative strategies may reduce the risk of developing breast and ovarian cancer and in some cases improve survival.

Newfoundland and Labrador (NL) is the most easterly province in Canada with a population of 525 983. It is geographically and genetically isolated with the majority of residents from English and Irish ancestry. While no one single founder effect has been identified, geographically distinct mutations for both BRCA 1 and 2 have been described. The objective of this study is to characterize the population of BRCA mutation carriers in NL and to evaluate their uptake of risk reducing interventions.

Methods

All BRCA 1 and 2 carriers tested through the Provincial Medical Genetics program between 1996 - 2018 were captured. Inclusion criteria for this study were females ≥ 18 years of age residing in the province. Demographic, clinical history and information on uptake of risk reducing interventions were abstracted from the electronic medical record. Descriptive statistical analysis was performed.

Results

One hundred and sixty one women were identified that met inclusion criteria (38% of patients had BRCA1 and 62% had BRCA 2 mutations). Of those unaffected carriers eligible for mammography and MRI screening, only 58% were adherent in the last 18 months. Consultation with a medical or gynecological oncologist increased mammogram screening within the last 18 months to 71% compared with 29% of women who did not see an oncologist. MRI screening increased to 80% for those assessed by oncology versus 20% who did not. For those women who underwent prophylactic surgeries, 27% had bilateral mastectomies with the majority having breast reconstruction (&gt;70%). Fifty two percent of carriers had bilateral salpingo-oophorectomies (BSO) at a median age of 45 years in BRCA 1 and 51 years in BRCA 2.

Fifty-three women had a diagnosis of breast cancer and 8 had ovarian cancer. In this cohort, most underwent genetic testing after their diagnosis of cancer (&gt;80%). Median age at presentation of breast cancer was 44 years versus 54 years for ovarian cancer.

Conclusion

This study demonstrates that women with BRCA 1 and 2 mutations are not adequately availing of risk reducing interventions for breast and ovarian cancer. Furthermore, most patients with malignancy did not undergo genetic testing until after they were diagnosed with cancer. Patient focused research designed to explore factors which may contribute is planned. Consultation with an oncologist increased the likelihood of adherence to breast cancer screening. This highlights the importance of specialty care for patients with a hereditary predisposition to breast and ovarian cancer.

Citation Format: Seal MD, Roebothan A, Gabriel A, Dawson L. Risk reducing interventions among BRCA 1 and 2 female carriers in Newfoundland and Labrador: A provincial analysis [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P5-09-17.