Detection of Germline Variants in Patients With Localized and Metastatic Prostate Cancer Through Guideline-Based Testing.

Introduction: There is increasing awareness that patients with prostate cancer frequently harbor germline variants that may carry important implications for them and their family members. Given the variable clinical guidelines, there remains a need to better understand which patients with prostate cancer are likely to harbor pathogenic or likely pathogenic (P/LP) germline variants. We sought to understand factors associated with P/LP germline variants in patients with metastatic or localized prostate cancer qualifying for National Comprehensive Cancer Network genetic testing criteria.

Methods: Patients diagnosed with prostate cancer were offered genetic testing in accordance with National Comprehensive Cancer Network guidelines. Patient-level factors, including demographic, clinical, and pathologic data, were tracked in a prospectively collected registry. The association of the presence of a P/LP variant in germline testing results with patient-level factors was assessed using univariate and multivariate logistic regression. Variables were tested for overall significance with χ tests.

Results: Five hundred five patients underwent germline testing and had clinical data available. Rates of P/LP germline variants were 7.6% (20/264) in patients with metastatic disease and 11.2% (27/241) in patients with localized disease. The most prevalent P/LP variants were (34%), (22%), (10%), and (10%).

Conclusions: In this cohort of patients undergoing guideline-informed germline testing, P/LP germline variants were found in similar proportions across all age ranges and clinical characteristics. Only age at genetic testing for patients with metastatic disease was demonstrated to be predictive of the presence of a P/LP germline variant, highlighting the challenges associated with refining current clinical testing guidelines.