NFS-12. CHOROID PLEXUS CARCINOMA IN PEDIATRIC PATIENTS WITH LI FRAUMENI SYNDROME (LFS) – CLINICAL COURSE AND THERAPEUTIC STRATEGIES

Abstract

Abstract BACKGROUND Choroid plexus carcinoma (CPC) is a rare pediatric brain tumor occuring predominantly in infancy. It is commonly associated with the cancer predisposition Li-Fraumeni syndrome (LFS). Management of CPC patients with LFS is challenging and there is no accepted standard treatment. This multinational retrospective analysis aimed to describe the clinical characteristics and outcome of pediatric patients with LFS-associated CPC. METHODS We identified 32 patients (male, n=24; median age at diagnosis 2.1 years [range, 0.3-13.2]) with CPC (CNS WHO grade 3), and LFS confirmed by the presence of (likely) pathogenic TP53 germline variants. In 29 patients, LFS was diagnosed after CPC. Seventeen patients (53%) had a positive family history of LFS. CPC arose from the lateral ventricles in 30 patients, 14 had metastases at diagnosis. RESULTS Gross total resection was achieved in 21 patients during first-line treatment, as was subtotal resection in 9 and partial resection/biopsy in 2 patients. Thirty-one patients received first-line chemotherapy, with carboplatin/etoposide/vincristine most commonly used (n=9). Eight patients received upfront irradiation (CSI, n=5). Complete remission (CR) and partial remission (PR)/stable disease (SD) was achieved in 20 and 5 patients, respectively. Six patients did not respond to first-line treatment and one patient died during initial surgery. Nineteen patients experienced relapse or progressive disease (PD) with a median progression-free survival of 2.2±1.0 years and with metastases in 79%. At a median follow-up of 1.9 (0.1-17.7) years, fourteen patients were alive in CR (n=10), SD (n=1) or PD (n=3) and eighteen patients died (CPC-related, n=14; other malignancies, n=4). Progression-free and overall survival at 2 and 5 years were 52.2±9.1%/32.8±8.9% and 65.6±8.9%/51.8±10%, respectively. CONCLUSIONS LFS-related CPC carries a poor prognosis but should not be considered incurable. Outcomes are not dissimilar to non-LFS-related TP53-mutated CPC. International collaboration is the prerequisite for treatment standardization.