LG-63: MANAGEMENT OF PRIMARY TECTAL LOW-GRADE GLIOMA (LGG) IN PEDIATRIC PATIENTS: RESULTS OF THE MULTICENTER TREATMENT STUDY SIOP-LGG 2004

BACKGROUND: Tectal LGG (TLGG) pose a therapeutic challenge, as resection may be associated with neurological damage and as the course of disease is highly variable ranging from patients observed without biopsy/treatment to those receiving repetitive multimodal treatment. METHODS: From 2004 until 2012, 71 patients with TLGG from Germany and Switzerland were followed within the SIOP-LGG 2004 study. Median follow-up was 6.3 (range, 2.9–15.9) years. For this analysis, tumor therapy (TT) was defined as at least partial resection, chemotherapy or radiotherapy. Event for EFS was defined as tumor progression, start of first TT, or death. RESULTS: 41 received no TT (12 biopsy/29 central radiological review only). 30 patients received TT (surgical only: 1 procedure, 11; >1 procedures, 3; chemotherapy only: 2; radiotherapy only: 9; multiple modalities: 5 patients). 5- and 10-year EFS (SE) were 42% and 40% (6% and 6%), respectively. 5-year EFS for patients with initial tumor volume ≤3 cm³ was 57% (8%) as opposed to 11% (7%) with >3 cm³ (p < 0.001). 5-year EFS for patients with initial contrast enhancement on MRI was 20% (8%) and 59% (9%) for those without (p = 0.002). 5- and 10-year OS were 99% (1%) and 96% (3%) (DOD, 1; ventriculoperitoneal shunt infection, 1). 88.7% of patients had at least 1 CSF diversion procedure. CONCLUSIONS: The SIOP-LGG 2004 strategy was feasible for TLGG. More than half of patients were managed without TT. Favorable prognostic factors for EFS were small initial tumor volume and absence of initial contrast enhancement on MRI. Overall survival was excellent.