EP12.06 EARLY CSF DISSEMINATION OF THALAMIC MALIGNANT GLIOMA IN ADULT: CASE SERIES OF 7 PATIENTS

Abstract BACKGROUND Thalamic gliomas constitutes 1-5% of intracranial tumors. They are common in children and high grade tumor is more frequently occurred in adult. The outcome of thalamic malignant gliomas (TMG) is dismal, reported overall survival is around 1 year. Early progression is a main factor of survival limitation of TMG and cerebrospinal fluid (CSF) dissemination is occasionally found during the progression. Authors report the case series of early CSF dissemination in adult patients with TMG. MATERIAL AND METHODS The clinical and radiological data of 26 adult patients with histologically proven thalamic gliomas were reviewed retrospectively. All patients were performed either resection or stereotactic biopsy, and followed by radiotherapy and/or chemotherapy. Of those, the patients with distant CSF dissemination were included. RESULTS Seven (26.9%) patients revealed the radiological distant CSF dissemination with mean 16.5 months (range, 3.5-35) after operation. Five patients were male and mean age was 38.7 years (range, 25-47). Pathological diagnosis was astrocytoma, grade 3 in 5 and diffuse midline glioma, H3 K27M-mutant in 2. As the first treatment, open resection or stereotactic biopsy was performed in 4 and 3, respectively. Adjuvant treatment was Stupp regimen (CCRT followed by temozolomide chemotherapy) in 2 and radiation followed by chemotherapy in 4. The distant dissemination was ventricles in 5, 4th ventricle with posterior fossa in 1, and cranio-spinal in 1. Four patients did not showed primary site progression. Six patients received additional chemotherapy (temozolomide or bevacizumab). Median survival after CSF dissemination was 5.3 months. CONCLUSION Early CSF dissemination seems to be an important factor of survival limitation in patients with TMG and it occurs in both cases of open surgery and stereotactic biopsy. The mechanism of frequent CSF dissemination in TMG is uncertain and it needed further investigation. Authors suggest that distant CSF dissemination should be considered in the treatment of TMG in adult.