CCRT With Temozolomide Versus RT Alone in Patients With IDH Wild-type/TERT Promoter Mutation Grade II/III Gliomas

The management of lower-grade gliomas (Diffuse low-grade and intermediate-grade gliomas, WHO II and III) is largely based on surgery followed by radiotherapy. Recent studies showed that lower-grade glioma patients with IDH wild-type (IDH-wt) and TERT promoter mutation (TERTp-mut) had dismal clinical outcomes. These results suggested that current treatment strategies are not adequate for this subtype of lower-grade glioma. The present study aims to examine the efficacy and safety of concurrent chemoradiotherapy with temozolomide followed by adjuvant temozolomide for lower- grade glioma patients with IDH-wt and TERTp-mut.

Diffuse low-grade and intermediate-grade gliomas (which together make up the lower-grade gliomas, World Health Organization grades II and III) are infiltrative neoplasms that arise most often in the cerebral hemispheres of adults and include astrocytomas, oligodendrogliomas, and oligoastrocytomas. The management of lower-grade gliomas is largely based on surgery followed by radiotherapy. Lower-grade gliomas have highly variable clinical behavior that is not adequately predicted on the basis of histologic class. Consequently, clinicians increasingly rely on genetic classification to guide clinical decision making. Mutations in IDH1 and IDH2 characterize the majority of lower-grade gliomas in adults and define a subtype that is associated with a favorable prognosis. Mutations of the telomerase reverse transcriptase (TERT) promoter, which result in enhanced telomerase activity and lengthened telomeres, have been observed in several human cancers including glioma. Accumulating evidence suggest that TERT promoter mutation is another molecular marker which can stratify lower-grade gliomas into prognostic subgroups in combination with IDH mutation. In our previous study, patients(28/377, 7.4%) who had lower-grade gliomas with IDH wild-type (IDH-wt) and TERT promoter mutation (TERTp-mut) had the poorest clinical outcomes (median OS, 27.7mo; 5-year OS, 29%). These results were accordant with the recent studies and suggested that current treatment strategies are not adequate for this subtype of lower-grade glioma. Radiotherapy plus temozolomide has emerged as a new standard of care for patients with good PS non-elderly glioblastoma. There are some data that support temozolomide as adjuvant therapy for lower-grade glioma. Given that the IDH-wt/TERTp-mut subgroup of lower-grade gliomas has dismal prognosis, a more aggressive therapy such as concurrent chemoradiotherapy seems to be reasonable. The present study aims to examine the efficacy and safety of concurrent chemoradiotherapy with temozolomide followed by adjuvant temozolomide for lower-grade glioma patients with IDH-wt and TERTp-mut. Half the patients will be randomly assigned to receive concurrent chemoradiotherapy (surgery + concurrent chemoradiotherapy with temozolomide followed by adjuvant temozolomide) and half the patients will be randomly assigned to receive conventional therapy (surgery + radiotherapy only).