Implementation and Audit of Mainstream Genetic Testing Within a High-Volume UK Breast Unit for Pathogenic Variations...

Area of Science:

• Oncology
• Medical Genetics
• Genomic Medicine

Background:

• An estimated 5%-10% of breast cancer cases are linked to inherited pathogenic or likely pathogenic (P/LP) variants.
• The UK National Test Directory established criteria (R208 and R444.1) for genetic testing and PARP inhibitor eligibility in breast cancer patients.

Purpose of the Study:

• To assess the incidence of P/LP variants in breast cancer patients meeting UK National Test Directory criteria.
• To evaluate the impact of genetic testing results on treatment decisions, including surgical options and PARP inhibitor eligibility.

Main Methods:

• Utilized NHS genomics criteria (R208/R444.1) to identify eligible breast cancer patients diagnosed between March 2021 and March 2025.
• Offered genetic testing to eligible patients and analyzed the incidence of P/LP variants.
• Examined the correlation between genetic results and subsequent treatment modifications.

Main Results:

• Of 196 patients who consented to testing, 28 (14.3%) had a P/LP variant.
• Family history criteria alone identified 8 eligible patients.
• Genetic results led to altered surgical plans for 14 patients and facilitated PARP inhibitor treatment for 3 patients.
• Eligibility assessment was noted as time-consuming for clinicians.

Conclusions:

• The 14.3% P/LP variant detection rate aligns with predictions, underscoring the importance of family history in genetic screening.
• Positive genetic test results significantly influenced surgical management and expanded access to PARP inhibitor therapy for eligible breast cancer patients.