RTHP-02. INTRACRANIAL BASAL GANGLIA/THALAMUS GERM CELL TUMOURS: CLINICAL CHARACTERISTICS, TREATMENT OUTCOMES, AND QUALITY OF LIFE OF 211 PATIENTS FROM A SINGLE CENTRE

PURPOSE Intracranial germ cell tumours (iGCTs) originating from the basal ganglia/thalamus (BG/T) region are rare. We report the findings from a large single-centre series to explore the clinical features of this disease. PATIENTS AND METHODS Patients diagnosed as having BG/T iGCTs from January 2000 to December 2017 at our hospital were screened. Newly diagnosed patients who had histology-proven/tumour marker-elevated disease and received at least radiotherapy were eligible for analysis. RESULTS Of the 401 patients screened, 211 were eligible. The median age was 12 years (range, 5–41 years). The median duration of follow-up for surviving patients was 68 months (range, 12–189 months). In germinoma patients (n = 112), the 5-year disease-free survival (DFS) and overall survival (OS) were 94.9% and 98.2%, respectively. Multivariate analysis showed that the dose of radiotherapy could predict the DFS (hazard ratio [HR] 0.991, 95% confidence interval [CI] 0.983–0.998, p = 0.015). In non-germinomatous GCT (NGGCT) patients (n = 99), the 5-year DFS and OS were 83.8% and 88.6%, respectively. Multivariate analysis showed that irradiation field (whole-brain radiotherapy vs. local radiotherapy, HR = 0.163, 95% CI 0.031–0.897, p = 0.037; cranial spinal radiotherapy vs. local radiotherapy, HR = 0.095, 95% CI 0.009–1.031, p = 0.053) and chemotherapy cycle (>3 vs. ≤3) (HR 0.234, 95% CI 0.055–0.996, p = 0.049) were independent factors for DFS. The median Z-score for height and body mass index (BMI) in patients ≤19 years of age (n = 69) at the last follow-up were -0.45 (range, -2.67 to 3.41) and 0.59 (range, -4.73 to 3.1), respectively. CONCLUSION BG/T GCTs had unique characteristics. Radiation dose was an independent factor influencing the DFS in cases of germinoma. In NGGCTs, extended field radiation and more chemotherapy cycles yielded better disease control. Physical development after treatment was within the normal range for most patients.