NFB-06. Laser Interstitial Thermal Therapy as a Radiation-Sparing Approach for Children with Cancer Predisposition

BACKGROUND: Li-Fraumeni (LFS) syndrome confers a predisposition for the formation of a broad range of tumors. Estimates of post-radiation secondary malignancy in the context of LFS cohorts range from 20-50%. Therefore, alternative therapeutic strategies are prioritized. Laser interstitial thermal therapy (LITT) is a minimally invasive technique utilizing thermal ablation for tumor control that is not associated with any ionizing radiation or known mutagenic effect. We describe the case of a child with LFS previously treated for CPC who developed a secondary low-grade glial neoplasm of the brain treated safely with MR-guided LITT as part of a radiation-sparing therapeutic approach. METHODS: Retrospective chart review identified a patient with recurrent CPC associated with LFS who was treated with LITT for a secondary low-grade glial tumor. A descriptive report is provided, including a review of clinical and radiologic outcomes of the procedure. RESULTS: A 4-year-old male with left parietal WHO Grade III CPC associated with a TP53 germline mutation met inclusion criteria. The patient underwent neoadjuvant platinum-based chemotherapy before near-total resection, followed by immunotherapy with 131I-8H9 and 30 fractions of 54Gy total proton therapy. He remained without evidence of disease for two years prior to developing a slow-growing mass adjacent to the left frontal horn. This lesion demonstrated radiographic progression on neuroimaging and was deemed to be a poor candidate for surgical removal. Stereotactic biopsy revealed a low-grade glial neoplasm staining positive for GFAP and Olig2. MR-guided LITT was concurrently performed for ablative therapy of the lesion without complication. Greater than 8-month follow-up has revealed no subsequent disease. CONCLUSIONS: Alternatives to ionizing radiation for brain tumors should be explored for patients with cancer predisposition, such as LFS. Long-term follow up will be needed to ensure local disease control and avoidance of treatment-related neoplasms.