STMO-19 Impact of aggressive resection for glioblastoma of the thalamus with histone H3-K27M mutation

Glioblastoma of the thalamus occurs predominantly in childhood and young adulthood, and cases with histone mutations are thought to have a particularly poor prognosis. We studied tumor resection rate, age, type of adjuvant therapy, and histone gene mutations on progression-free survival (PFS) and overall survival (OS) in patients who underwent aggressive removal. Eight cases of thalamic glioblastoma were included in the study. The mean age at surgery was 36.1 years (10–74 years, 3 cases under 18 years). Tumor removal was performed from the parieto-occipital lobe to the thalamus via the lateral ventricles in all cases. In all cases, more than 90% of the contrast-enhancing lesions were removed. Postoperatively, one patient had sensory disturbance of the left upper limb, and the other had incomplete paralysis of the left upper and lower limbs, but both were able to walk with a cane. In the case of the patient with postoperative complications, the tumor was located in the vicinity of the internal capsule. All patients were treated with radiation therapy and temozolomide, and bevacizumab and Novo-TTF were used in cases after approval. All patients were able to return home and return to school or work after initial treatment. The mean progression-free survival (PFS) was 0.87 years, and overall survival (OS) was 1.95 years. Five patients had histone H3-K27M mutations, and three patients had no mutations. PFS and OS were 1.02 years and 0.62 years, respectively, and 2.53 years and 1.20 years, respectively, both of which were longer in patients with mutations (PFS; p=0.16, OS; p=0.23).Aggressive removal of glioblastoma of the thalamus may improve prognosis, especially in patients with histone H3-K27M mutations. In patients with tumors extending to the vicinity of the internal capsule, total removal may cause paralysis and sensory disturbance.