P17.49 * TREATMENT STRATEGY FOR WHO GRADE III GLIOMAS: THE LESSONS LEARNED FROM THE RETROSPECTIVE MULTICENTER ANALYSIS OF 243 PATIENTS

Abstract

OBJECTIVE: This retrospective analysis was performed to determine the efficacy, safety, and tolerability of treatment protocols including radiation therapy, concurrent chemoradiotherapy (CCRT) followed by adjuvant chemotherapy with temozolomide (TMZ), or PCV chemotherapy based on the status of molecular diagnosis in the treatment of patients with WHO grade III gliomas. MATERIALS: Two hundred forty three adult patients with WHO grade III glioma and aged > 17 years were enrolled from two institutions between 2004 and 2012. The pathological diagnoses were anaplastic astrocytomas (AA) in 150 patients and anaplastic oligodendrogliomas (AO) including anaplastic oliogoastrocytomas in 93 patients. Co-deleted group on 1p19q LOH analysis was 60 of available 183 patients and un-methylated group of MGMT promoter was 64 of available 170 patients. The AA patients received four different treatment protocols in same strategy in two institutions: radiation therapy only, CCRT with temozolomide, radiation therapy followed by PCV or temozolomide adjuvant chemotherapy, and nothing after surgery. The AO patients received also four different treatment protocols in same strategy in two institutions: radiation therapy only, CCRT with temozolomide, radiation therapy combined with PCV (neo- or) adjuvant chemotherapy, and temozolomide chemotherapy only after surgery. RESULTS: Overall survival (OS) and progression free survival (PFS) were superior in AO (98m and 61m) than in AA (34m and 23m) and 1p19q co-deleted group had significantly longer OS (98m vs 42m) and PFS regardless treatment protocols. In AA patients RT only group and CCRT with temozolomide group had the better OS and PFS than other two groups. Methylation status of MGMT promoter in these patients did not affect survival differences. In AO patients RT only group, PCV based chemotherapy group (neoadjuvant or adjuvant PCV), or CCRT with temozolomide groups had no statistically significant differences in survival data. However 1p19q co-deleted group had a much better survival data (OS 98m vs 53; PFS not reached yet vs 38m). CONCLUSION: 1p19q co-deletion (molecular diagnosis) may be more important than morphologic diagnosis in grade III gliomas. The methylation status of MGMT promoter is not important such as in case of grade IV, glioblastoma. Adjuvant PCV might improve OS and PFS in AO regardless of the timing of PCV, either pre-RTx. or post-RTx. CCRTx. with TMZ may improve OS in non co-deleted group and this will be one of good candidate for standard one. A randomized controlled study with a long-term follow-up may be mandatory to evaluate and to make a best treatment protocol for these tumors.