Session # Abstract Poster# 614

Lifetime risk of breast cancer from polygenic risk scores combined with clinical assessment in women referred for genetic testing

• Average lifetime risk estimated by clinical models for women referred for genetic testing is high (mean Tyrer-Cuzick estimated lifetime risk was ~23%, and ~60% of women had lifetime risk >20%).
• Among women with lifetime risk <20% based on Tyrer-Cuzick alone, most had a clinical-PRS combined lifetime risk <20%. The clinical-PRS lifetime risk was >20% threshold for ~20% of these women (19.0% and 1.4% had combined risks ranging 20-50% and >50%, respectively).
• The majority of women whose combined risk was elevated above the 20% threshold had moderate Tyrer-Cuzick risk (10-20%) and high PRS. Therefore, a high PRS may result in an increased lifetime risk estimate for women who would otherwise have modest clinically-estimated risk.

• Authors: Mary Helen Black; Stephanie Gutierrez; Shuwei Li; Jill Dolinsky; Jessica Profato; Holly LaDuca
• Conference: ACMG 2019
• Date: Friday, Apr 05, 2019 10:30am - 12:00pm