Abstract
INTRODUCTION: Anaplastic oligodendrogliomas are rare diffuse gliomas. Although radiotherapy (RT) combined with procarbazine, lomustine, and vincristine (PCV) has been the historical standard, temozolomide (TMZ) has been increasingly used. OBJECTIVE: To compare the efficacy of RT combined with PCV versus RT combined with TMZ in adult with anaplastic oligodendroglioma. METHODS: A systematic search of PubMed, Embase, and the Cochrane Library was conducted up to March 2025. Eligible studies included patients with 1p/19q-codeleted anaplastic oligodendroglioma treated with RT + PCV, RT + TMZ, or RT alone. Studies comparing RT alone to RT + PCV or RT + TMZ were used to create indirect comparisons, with RT as a common comparator. A frequentist network meta-analysis with a random-effects model was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for overall survival (OS) and progression-free survival (PFS). Risk of bias was assessed with RoB 2 and ROBINS-I. The protocol was registered in PROSPERO (CRD420251012169). No funding was received. RESULTS: Eight studies comprising 2,416 patients were included. The network meta-analysis, compared with RT alone, RT + PCV significantly improved OS (HR: 0.617; 95% CI 0.465-0.819; p = 0.0009), and PFS (HR: 0.547; 95% CI 0.415-0.721; p < 0.0001), while RT + TMZ showed a trend toward improved OS (HR: 0.913; 95% CI 0.666-1.252; p = 0.421) and PFS (HR: 1.270; 95% CI 0.870-1.855; p = 0.215), without statistical significance. In the comparison between RT + PCV and RT + TMZ, RT + PCV demonstrated superior OS (HR: 0.676; 95% CI, 0.585-0.781; p < 0.0001) and better PFS (HR: 0.431; 95% CI, 0.325-0.570; p < 0.0001). Limitations include the small number of randomized trials directly comparing key outcomes, and the fact that most studies predated current molecular diagnostic criteria, with toxicity data often reported in heterogeneous populations. CONCLUSION: In patients with anaplastic oligodendroglioma, RT combined with PCV provides superior survival outcomes compared to radiotherapy combined with TMZ.