Efficacy of initial temozolomide for high-risk low grade gliomas in a phase II AINO (Italian Association for Neuro-Oncology) study: a post-hoc analysis within molecular subgroups of WHO 2016
The optimal management of high risk WHO grade II gliomas after surgery is debated including the role of initial temozolomide to delay radiotherapy and risk of cognitive defects.
A post-hoc analysis of a phase II multicenter study on high risk WHO grade II gliomas, receiving initial temozolomide alone, has re-evaluated the long-term results within the molecular subgroups of WHO 2016. The primary endpoint of the study was response according to RANO, being seizure response, PFS and OS secondary endpoints.
Response rate among oligodendrogliomas IDH-mutant and 1p/19q codeleted (76%) was significantly higher than that among diffuse astrocytomas either mutant (55%) or wild-type (36%). A reduction of seizure frequency > 50% was observed in 87% of patients and a seizure freedom in 72%. The probability of seizure reduction > 50% was significantly associated with the presence of an IDH mutation. Median PFS, PFS at 5 and 10 years, median OS and OS at 5 and 10 years were significantly longer in oligodendrogliomas IDH-mutant and 1p/19q codeleted. Sixty-seven percent of patients with oligodendroglioma IDH mutant and 1p/19q codeleted did not recur with a median follow up of 9.3 years, while 59% did not receive radiotherapy at recurrence with a median follow up of 8.2 years.
The beneficial effects of initial temozolomide prevail in oligodendrogliomas IDH-mutant and 1p/19q codeleted: thus, these tumors, when incompletely resected or progressive after surgery alone, or with intractable seizures, should receive temozolomide as initial treatment with salvage radiotherapy and/o reoperation and/or second-line chemotherapy at recurrence.
KeywordsGrade II gliomas WHO 2016 Oligodendrogliomas IDH-mutant and 1p/19q codeleted Temozolomide Response Survival
Conception and design: Roberta Rudà, Alessia Pellerino, Riccardo Soffietti. Provision of study materials or patients: All authors. Collection and assembly of data: Alessia Pellerino, Giulia Marchese. Statistical analysis: Enrica Migliore. Article writing: Roberta Rudà, Alessia Pellerino, Riccardo Soffietti. Final approval of article: All authors.
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Conflict of interest
The authors have declared no conflict of interest.