Only 32.3% of Breast Cancer Families with Pathogenic Variants in Cancer Genes Utilized Cascade Genetic Testing

Area of Science:

• Genetics
• Oncology
• Preventive Medicine

Background:

• Hereditary cancer predisposition syndromes account for 5-10% of cancer cases.
• Cascade family testing (CFT) targets relatives of individuals with known pathogenic variants (PVs/LPVs).
• This study focuses on CFT implementation in breast cancer families.

Purpose of the Study:

• To investigate the clinical use and implementation of cascade family testing (CFT).
• To assess CFT in families of breast cancer patients with pathogenic/likely pathogenic variants (PVs/LPVs).

Main Methods:

• Germline sequencing utilized a 52-gene panel via NGS technology.
• Cascade testing employed Sanger sequencing or MLPA methods.

Main Results:

• 20.3% of 1785 breast cancer patients had PVs/LPVs.
• Only 32.3% of families proceeded with CFT, primarily in high-risk gene families.
• Of relatives tested, 89.3% were cancer-free, predominantly females (70.3%).

Conclusions:

• CFT is a valuable tool for primary cancer prevention by identifying at-risk individuals.
• Enhanced genetic counseling is crucial for increasing awareness and uptake of CFT.
• Effective communication of genetic testing results is vital for successful implementation.