CTNI-20. PCV CHEMOTHERAPY ALONE IS ASSOCIATED WITH BETTER CLINICAL COURSE IN OLIGODENDROGLIOMA WHO GRADE II

Abstract

Abstract BACKGROUND Current treatment guidelines for oligodendrogliomas (OD) recommend watch-and-wait strategies after gross total resection and radiation with subsequent chemotherapy (procarbazine, CCNU and vincristine (PCV)) after incomplete resection. The value of chemotherapy alone as an option to delay the risk of late cognitive deficits is not well defined yet. Here, we retrospectively investigated long-term outcome in OD WHO II with respect to initial therapy and tumor volume in magnetic resonance imaging (MRI). METHODS A total of 142 patients with OD WHO (World Health Organization) II according to WHO 2016 were retrospectively included. Patients either had watch and wait (W&W) after histological sampling through stereotactic biopsy (n=59) or tumor resection (n=27) or else stereotactic biopsy with subsequent temozolomide (TMZ) (n=26) or PCV (n=30). Pre- and post-therapeutic T2 tumor volumes were obtained. Progression-free survival (PFS), post-recurrence PFS (PR-PFS) and rate of secondary malignization after 10 years (MR-10yrs) were correlated with clinical and volumetric data. RESULTS PFS was significantly longer in the PCV cohort compared to TMZ (9.1 vs. 3.6 years, p = 0.04), even after matching patients according to age and initial tumor volume (9.1 vs 4.7 yrs, p = 0.03). PFS in the W&W cohort was 5.1 years and 4.4 years in those receiving tumor resection only. MR-10yrs was 4% in PCV cohort, 18% in the W&W cohort and 52% in the resection only cohort (p = 0.01). In the W&W cohort, patients treated with PCV at first relapse had a longer PR-PFS than those treated with TMZ (in years, 7.2 vs 4.0, p = 0.04). Multivariate analysis confirmed initial PCV therapy (p = 0.01) and initial T2 tumor volume (p = 0.02) to be prognostic. CONCLUSION In oligodendrogliomas WHO II PCV chemotherapy alone is superior in terms of PFS and rate of secondary malignization compared to TMZ chemotherapy alone or tumor resection only.