When Should Tumor Genomic Profiling Prompt Consideration of Germline Testing?

Somatic genomic testing is rapidly becoming an integral part of care for patients with metastatic cancer. Extrapolation of these results beyond personalized cancer therapy is a skill being demanded of practicing oncologists without prior specialty in genetics. Up to 12% of tumor genomic profiling reports will reveal a germline pathogenic variant. Recognition of these germline variants is essential not only for optimal care of the patient with cancer but also to initiate cascade genetic testing in at-risk family members who also may carry the familial mutation. This article provides a concise and methodical, evidence-based strategy to guide oncology providers about how to identify genes associated with an inherited predisposition for cancer, determine the pathogenicity of variants reported within those genes, and understand the likelihood that these variants are of germline origin in a particular patient with cancer. Case examples are provided to illustrate clinical scenarios and facilitate application of the proposed approach.