Pediatric oncologist willingness to offer germline TP53 testing in osteosarcoma

BACKGROUND: Li-Fraumeni syndrome (LFS) is a cancer predisposition syndrome caused by mutations in the tumor-suppressor gene TP53. Osteosarcoma is a sentinel cancer in LFS. Prior studies using Sanger sequencing platforms have demonstrated that 3% of individuals with osteosarcoma harbor a mutation in TP53. New data from next-generation sequencing have demonstrated that 3.8% of patients with osteosarcoma have a known pathogenic variant, and an additional 5.7% carry exonic variants of unknown significance in TP53. METHODS: Pediatric oncologists were e-mailed an anonymous 18-question survey assessing their willingness to offer TP53 germline testing to a child with osteosarcoma with or without a family history, and they were evaluated for changes in their choices with the prior data and the new data. RESULTS: One hundred seventy-seven pediatric oncologists (22%) responded to the survey. Respondents were more likely to offer TP53 testing to a patient with a positive family history (77.4% vs 12.4%; P <.0001). Significantly more providers responded that they would offer TP53 testing once they were provided with the new data (25.4% vs 12.4%; P =.0038). The proportion of providers who responded that they were unsure increased significantly when they were presented with the new data (25.4% vs 10.2%; P =.0002). Potential implications for other family members and the possibility that surveillance imaging would detect new malignancies at an earlier stage were important factors influencing a provider's decision to offer TP53 testing. CONCLUSIONS: Recent data increase the proportion of providers willing to offer testing, and this suggests concern on the part of pediatric oncologists that variants of unknown significance may be disease-defining in rare cancers. Cancer 2018;124:1242-50.