10126-ACT-10 FACTORS AFFECTING THE PATTERN OF RECURRENCE OF IDH-WILDTYPE GLIOBLASTOMA

Abstract

Abstract INTRODUCTION IDH-wildtype glioblastoma is a quite poor prognosis disease with which almost all cases recur in spite of postoperative radiation and chemotherapy. Survival rates are particularly low after dissemination. METHODS We included 120 patients with IDH-wild type glioblastoma treated at our hospital from January 2015 to December 2019. Patient backgrounds, MGMT promotor methylation status, imaging findings, and recurrence patterns were analyzed. Subependymal, subarachnoid, and spinal dissemination, plus distant metastasis, were defined as non-local recurrence. RESULTS Of 105 patients with a single lesion at diagnosis, 65 had local recurrence and 15 had non-local recurrence. 36 of 65 patients had local recurrence and 12 had non-local recurrence in the second recurrence. 17 of 36 patients had local recurrence and 8 had non-local recurrence in the third recurrence. The cumulative number of non-local recurrences was 54 (45.0%). Surgical ventricular opening and tumor proximity to the ventricles were associated with non-local recurrence (p=0.006, p=0.019). The patients with tumor proximity to the ventricle had non-local recurrence at the first recurrence and those with non-proximity to the ventricle had non-local recurrence at the second or later recurrence (p=0.038). MGMT promotor methylation status and postoperative ischemia were not significantly different from non-local recurrence (p=0.122, p=0.088), but MGMT promotor unmethylation was a risk factor for early non-local recurrence, especially within 1 year (p=0.033). Frontal lobe lesions were less frequently disseminated and more frequently MGMT promotor methylated (p=0.032, p=0.024). Parietal lobe lesions had more MGMT promotor methylation (p=0.006), and temporal lobe lesions had more dissemination (p=0.023). Distant metastasis commonly occurred from the frontal lobe to the ipsilateral or contralateral, and the frontal lobe was frequently associated. CONCLUSION IDH-wildtype glioblastoma is characterized by repeated local recurrence and cumulative non-local recurrence. The pattern of recurrence differs depending on the tumor localization, especially adjacent to ventricle, and MGMT promotor methylation status.