Genetic Testing Utilization: Discrepancies Between Somatic and Germline Results in Patients With Cancer Reviewed at the UW Health Precision Medicine Molecular Tumor Board.

purposeSomatic and germline testing are increasingly used to estimate risks for patients with cancer. Although both germline testing and somatic testing can identify genetic variants that could change a patient's care and eligible treatments, the aims of these tests and their technologies are fundamentally different and cannot be used interchangeably. This study examines the timing and results of somatic and germline genetic testing for patients with cancer at UW Health.

methodsEight hundred and seventy-seven participants underwent somatic genetic testing, which was reviewed by the Precision Medicine Molecular Tumor Board (PMMTB). Patients were diagnosed with cancers, including breast, colorectal, endometrial, pancreatic, or ovarian cancer, and met National Comprehensive Cancer Network criteria for germline genetic testing. Germline testing details were collected by medical record review.

resultsThe results of this study found that only 310 patients (35%) had germline evaluation before PMMTB review. The percent of germline pathogenic/likely pathogenic variants identified in actionable genes was 28%. Most germline variants were identified in the

conclusionThis study highlights the differences in genetic testing types and demonstrates that conducting germline testing at earlier stages of diagnoses is necessary to identify potentially actionable and treatment-specific variants in patients with cancer.