Parental Preferences Surrounding Timing and Content of Consent Conversations for Clinical Germline Genetic Testing Following a Child's New Cancer Diagnosis

Looking beyond year 1 in the molecular era of pediatric brain tumor diagnosis: confirmatory testing of germline variants found on tumor sequencing

Purpose

Somatic molecular profiling of pediatric brain tumors aids with the diagnosis and treatment of patients with a variety of high- and low-grade central nervous system neoplasms. Here, we report follow-up targeted germline evaluation for patients with possible germline variants following tumor only testing in the initial year in which somatic molecular testing was implemented at a single institution.

Patients and Methods

Somatic testing was completed for all tumors of the central nervous system (CNS) undergoing diagnostic workup at Seattle Children's Hospital during the study period of November 2015 to November 2016. Sequencing was performed in a College of American Pathologists-accredited, Clinical Laboratory Improvements Amendments-certified laboratory using UW-OncoPlex™ assay (version 5), a DNA-based targeted next generation sequencing panel validated to detect genetic alterations in 262 cancer-related genes. We tracked subsequent clinical evaluation and testing on a subgroup of this cohort found to have potential germline variants of interest.

Results

Molecular sequencing of 88 patients' tumors identified 31 patients with variants that warranted consideration of germline testing. To date, 19 (61%) patients have been tested. Testing confirmed germline variants for ten patients (31% of those identified for testing), one with two germline variants (NF1 and mosaic TP53). Eight (26%) patients died before germline testing was sent. One patient (13%) has not yet had testing.

Conclusion

Clinically validated molecular profiling of pediatric brain tumors identifies patients who warrant further germline evaluation. Despite this, only a subset of these patients underwent the indicated confirmatory sequencing. Further work is needed to identify barriers and facilitators to this testing, including the role of genetic counseling and consideration of upfront paired somatic-germline testing.

Parental Understanding of Their Child's Germline Genomic Testing: Intent of Disclosure to Their Child and Family

Genomic testing is becoming increasingly common in the care of pediatric patients with cancer. Parental understanding of germline results and their intent and timing of results disclosure to their child and family may have significant implications on the family unit. The purpose of this study was to examine parental understanding of germline genomic results and plans for disclosure to their child and other relatives. Semi-structured interviews were conducted with 64 parents of children with cancer, approximately eight weeks after parents had received their child's results. Parents of children with negative results (n = 20), positive results (n = 15), or variants of uncertain significance (n = 29), were interviewed. Fifty-three parents (83%) correctly identified their child's results as negative, uncertain, or positive. Most parents had disclosed results to family members; however, only 11 parents (17%) acknowledged discussing results with their child. Most parents delayed disclosure due to the young age of their child at the time of testing. In summary, most parents appropriately described their child's germline genomic results, yet few discussed the results with their child due to age. Families should be followed with supportive counseling to assist parents in the timing and content of result disclosure to their children.