Cancer Risk Assessment and Hereditary Cancer Genetic Testing in a Community OBGYN Setting

American Cancer Society, American College of Obstetricians and Gynecologists, American College of Radiology, The American Society of Breast Surgeons, National Comprehensive Cancer Network, and United States Preventive Services Task Force recommend cancer risk assessment and hereditary cancer genetic testing for appropriate individuals. It has been previously estimated that approximately 24% of unaffected patients meet national guidelines for hereditary cancer testing. Given the recent expansion of hereditary cancer genetic testing guidelines and improved understanding of the impact of genetic test results on patient management, we set out to determine the percent of unaffected patients meeting updated genetic testing criteria, outline breast cancer risk assessment and genetic test results, and delineate the percent of patients in whom management change would be recommended.

This process-intervention study included the implementation of a hereditary cancer risk assessment process for patient identification at 5 unique community obstetrics and gynaecology (OBGYN) practice sites from September 2021 to November 2022. Myriad Genetics' team of certified genetic counselors provided pre-test patient education. Germline genetic testing used the MyRisk multigene panel and additional breast cancer risk stratification was based on the Tyrer-Cuzick breast cancer risk model and RiskScore. Results disclosure and care management was performed and/or coordinated though the community OBGYN provider. Descriptive statistics were used for the analysis, including genetic screening and testing completion rates.

Sample Size: 5135 (4553/5135 [88.7%] provided a family history) Met NCCN Testing Criteria: 1285/4553 (28.2%) Patients offered Genetic Testing of those who met guidelines: 1145/1285 (89.1%) Submitted a Sample for Genetic Testing: 515/1145 (44.97%) Completed Testing: 439/515 (85.2%) Number of Patients with Pathogenic Variants* - 14/439 (3.2%): 1 BRCA2, 2 PALB2, 4 CHEK2, 1 MSH6, 1 PMS2, 1 BRIP1, 1 RAD51C, 2 HOXB13, 2 MITF *1 patient was a carrier of >1 pathogenic variants. Tyrer-Cuzick and RiskScore Risk Assessment: Overall % of women with a lifetime risk of breast cancer ≥20%: 36.5%.

More than 28% of individuals meet national guideline criteria for genetic testing, a clinically meaningful increase from previous findings of 24%. In addition, 36.5% of patients in which pathogenic variants were not identified are also deemed to be at elevated risk for breast cancer and warrant considerations for medical management change. Comprehensive cancer risk assessment identifies patients at elevated risk and helps to ensure that medical management is tailored to the appropriate risk level for each patient.