Short-term outcomes associated with temozolomide or PCV chemotherapy for 1p/19q-codeleted WHO grade 3 oligodendrogliomas: A national evaluation

Background The optimal chemotherapy regimen between temozolomide and procarbazine, lomustine, and vincristine (PCV) remains uncertain for WHO grade 3 oligodendroglioma (Olig3) patients. We therefore investigated this question using national data. Methods Patients diagnosed with radiotherapy-treated 1p/19q-codeleted Olig3 between 2010 and 2018 were identified from the National Cancer Database. The overall survival (OS) associated with first-line single-agent temozolomide vs multi-agent PCV was estimated by Kaplan-Meier techniques and evaluated by multivariable Cox regression. Results One thousand five hundred ninety-six radiotherapy-treated 1p/19q-codeleted Olig3 patients were identified: 88.6% (n = 1414) treated with temozolomide and 11.4% (n = 182) with PCV (from 5.4% in 2010 to 12.0% in 2018) in the first-line setting. The median follow-up was 35.5 months (interquartile range [IQR] 20.7-60.6 months) with 63.3% of patients alive at the time of analysis. There was a significant difference in unadjusted OS between temozolomide (5-year OS 58.9%, 95%CI: 55.6-62.0) and PCV (5-year OS 65.1%, 95%CI: 54.8-73.5; P = .04). However, a significant OS difference between temozolomide and PCV was not observed in the Cox regression analysis adjusted by age and extent of resection (PCV vs temozolomide HR 0.81, 95%CI: 0.59-1.11, P = .18). PCV was more frequently used for younger Olig3s but otherwise was not associated with patient's insurance status or care setting. Conclusions In a national analysis of Olig3s, first-line PCV chemotherapy was associated with a slightly improved unadjusted short-term OS compared to temozolomide; but not following adjustment by patient age and extent of resection. There has been an increase in PCV utilization since 2010. These findings provide preliminary data while we await the definitive results from the CODEL trial.