Top Line: The CODEL trial was originally designed to determine if radiation alone, radiation + temozolomide, or temozolomide alone was the best treatment for WHO grade III 1p19q codeleted oligodendroglioma.
The Study: However, it underwent major revisions after initiation. When the long-term results of RTOG 9402 and EORTC 26951 showed major improvement in survival (especially with 1q/19q codeletion) when PCV was added to radiation, the radiation alone arm was converted to radiation + PCV. The TMZ alone arm was also dropped after initial results suggested inferior outcomes compared to radiation arms. Thus, CODEL is now a comparison of radiation + TMZ and radiation + PCV. This report describes outcomes for the 36 patients enrolled in the original study design. Obviously, these results are not adequately powered, but they provide an insightful comparison of treatment approaches that were common at the time. After median follow-up of > 7 years, 83% of TMZ alone patients had disease progression compared to just 37.5% in the radiation arms. At the 5 year mark, progression-free survival was 33% with TMZ versus 56% with radiation. It cleary wasn't powered to detect a significant difference, but the discrepancy in overall survival at 5 years was noteworthy at 67% after TMZ alone versus 91% with radiation. Lastly, there was no difference in the rate of cognitive decline 3 months after treatment (67% versus 75%, respectively).
TBL: “Treatment with TMZ alone of newly diagnosed patients with 1p/19q codeleted WHO grade III oligodendroglial tumors was associated with significantly inferior progression-free survival compared with radiation.” | Jaeckle, Neuro Oncol 2021