1240 Assessing Survival Outcomes of PCV-Based and Temozolamide-Based Adjuvant Therapy in Oligodendroglioma Patients

INTRODUCTION: When treating oligodendroglioma patients, choosing between temozolomide (TMZ) and procarbazine, lomustine, and vincristine (PCV), with concurrent radiotherapy still poses a challenge. Given the commonality of tumor recurrence, optimizing progression-free survival while minimizing adverse effects is crucial to improving quality of life. METHODS: 87 patients treated for oligodendroglioma between 1994-2022 were retrospectively reviewed. Progression-free survival (PFS) and overall survival (OS) from initial resection were compared between PCV-based or TMZ-based treatment groups using Kaplan-Meier and multi-variable Cox survival analysis. RESULTS: The median age at diagnosis was 41 years and 62% were male. After initial resection, 42.8% received PCV-based treatment and 57.2% received TMZ-based treatment. Treatment groups were balanced in the following variables: age, tumor genetic profiling, the extent of resection, and KPS score. However, more patients in the TMZ-based group received concurrent radiation. The entire cohort had a 6.3-year PFS and 21.0-year OS. The median time to recurrence was significantly longer in those treated with PCV (12 years) compared to those treated with TMZ (4.7 years). PFS HR = 0.46, p = 0.04 and OS HR = 0.26, p = 0.04 were significantly longer in those receiving PCV-based treatment compared to TMZ-based treatment. After adjusting for previously mentioned variables, Cox regression analysis revealed no difference in OS between PCV- and TMZ-based treatment. The overall adverse effect rate did not significantly differ between PCV-based and TMZ-based treatment (25% vs. 28.1%, p > 0.99). CONCLUSIONS: PCV treatment confers longer progression-free survival than TMZ treatment for oligodendroglioma patients, noting that most patients in our series received concurrent radiation with TMZ, and those receiving PCV not having received upfront radiation. As we anticipate the results of the CODEL trial, our findings suggest PCV-based therapy warrants consideration as the preferred therapeutic option for oligodendroglioma patients.