Background: Next-generation sequencing (NGS) for tumor molecular profiling is used in Oncology to identify ‘actionable alterations’ for clinical trials or on/ off-label therapy. Tumor NGS can also reveal potentially heritable germline mutations. The frequency of such incidental germline mutations has been estimated to be 4-15%. The 2015 ASCO Statement supports communication of medically relevant incidental germline findings from somatic mutation profiling to patients (PTS). The impact of tumor NGS testing on hereditary cancer risk assessment programs in the context of a wider population management strategy is unknown. We sought to evaluate this within our Kaiser Permanente Northern California (KPNC) population with ready access to tumor NGS and an ongoing hereditary cancer risk assessment program. 

Methods: Kaiser Permanente Northern California (KPNC) is part of a large, integrated health care system. NGS at KPNC is performed in collaboration with STRATA Oncology, a precision oncology partnership. All NGS results are reviewed by a multidisciplinary KPNC Genomic Oncology Committee (GOC)which also includes genetic counselors and pathologists. We examined all NGS reports between November 2017 through December 2019 to determine the types of cancers tested, number with a possible germline mutation and number referred for genetic counseling and testing (GCT). 

Results: 4,825 PTS with advanced cancer underwent STRATA NGS testing. A total of 207 PTS (4.3%) were identified as potential germline mutation carriers, all 207 were recommended for GCT referral. Of these, 92 (45.0%) separately met 2020 NCCN Criteria for Genetic/Familial High-Risk Assessment (2020NG/FA), prior to tumor NGS; 115 (53.6%) did not and 3 (1.4%) had insufficient information. The cancers most frequently meeting NCCN criteria were pancreatic, breast and colon. Of the 92 PTS who met 2020NG/FA, 60 (65%) underwent GCT and 34 (57%) were confirmed to have a germline mutation. Of the 115 PTS that did not meet 2020NG/FA, 47 (41%) underwent GCT and 19 (40%) were confirmed to have a germline mutation. Overall germline mutations were confirmed in 16.5% of patients who did not meet 2020NG/FA and 37% who did. 

Conclusions: In our community-based integrated healthcare system, systematic review of next-generation sequencing results by an expert GOC led to more robust identification of germline mutation carriers and navigated them to appropriate GCT. Ongoing work will clarify data on cascade testing. We are currently developing automated workflows for GCT.