A129: The challenges of genetic testing in patients diagnosed with Breast Cancer; the Kent Oncology Center experience

Christos Mikropoulos1,Julia Hall1,Gill Sadler1,Aaron Davies1,Charlotte Abson1

1Kent Oncology Center, Maidstone, Kent, UK,2Institute of Cancer Research, London, UK

Presenting date: Monday 2 November
Presenting time: 12.20-13.10

Background

 

 

Breast cancer (BrCa) is by far the most common cancer among women in the UK, accounting for 30% of all new cases of cancer in females. According to NICE guidelines we should be offering genetic testing if the risk of being a BRCA carrier is over 10%. In patients with familial breast cancer, as defined by the National Comprehensive Cancer Network (NCCN), a specific predisposing gene is identified in up to 30% of cases, According to the TNT trial results patients with a triple negative BrCa diagnosis under the age of 50years had a BRCA1 mutation prevalence of 20%.

 

Method

 

We acquired patient data for all new breast cancer cases from Jan 2014 to June2014 from three referral centres in Kent. We examined the prevalence of bilateral breast cancer, triple negative breast cancer, male breast cancer, family history details and calculated the Manchester risk score for all new BrCa referrals and correlated this with genetic testing results using descriptive statistics

Results

 

 

207 new BrCa cases (2 male) were referred to Oncology in this period with 10% being triple negative, 10% with bilateral breast cancer and with 30% having at least one affected relative.  11/207 (5.3%) were eligible for genetic testing based on the NCCN guidelines.  6/11 patients underwent genetic testing with 1 found to carry a pathogenic BRCA2 mutation and 1 a TP53 mutation (Li-Fraumeni) and 4 found not to carry a pathogenic mutation. 5/11 patients eligible on the NCCN guidelines (3 patients with a Manchester score of over 15 and 2 patients with family history of ovarian cancer) did not undergo genetic testing.  A further 7/207 (3.4%) were eligible for genetic testing based on the current TNT trial data, which were not available during early 2014, making a total of 18/207 (8.7%) eligible.   We estimate that 3 potential BRCA carriers were not identified.

 

Conclusion

 

Genetic referral pathways could be optimised to take into account both the family history as well as phenotypical characterisitics (triple negative BrCa, bilateral BrCa) often associated with a germline DNA repair pathway mutation