Experiences of a multidisciplinary genomic tumor board interpreting risk for underlying germline variants in tumor-only sequencing results

PURPOSE Although analyzing germline and tumor samples concurrently provides the best opportunity for differentiating between germline and somatic mutations, tumor-only sequencing is becoming increasingly common in clinical care. The purpose of this study is to assess how a multidisciplinary genomic tumor board (MGTB) evaluated patients' tumor-only sequencing results and made genetics referrals. With limited professional society guidance on how to manage pathogenic mutations identified via tumor-only sequencing, this study contemplates the professional knowledge and skills necessary to have represented on an MGTB to interpret these results in context of potential germline findings. METHODS Qualitative interviews with MGTB members and an ethnographic case study of a breast cancer MGTB at a National Cancer Institute cancer center were examined. RESULTS This MGTB discussed 34 cases of women with advanced-stage breast cancer over 13 months. Interviews and observations of MGTB meetings indicated that members of the MGTB contemplated whether variants were germline or somatic and potential for identification of germline cancer predisposition. On the basis of existing professional society guidelines, 18 patients would be eligible for germline testing. However, the MGTB only referred 11 patients (61%) for additional germline testing, and the remaining seven patients (39%) were not referred, raising questions about the kind of genomic expertise needed on an MGTB to optimize results interpretation and referrals. CONCLUSION To ensure adequate interpretation, recommendation, and communication of tumor sequencing results, an MGTB should include professionals with knowledge and experience in clinical translation of tumor sequencing, testing methodology, molecular pathology, cancer biology, genomic pathways, germline variant interpretation, evaluation of family history, and application of professional recommendations for germline testing after tumor-only sequencing. These skills may not be held by a single professional on an MGTB.