[The Role of Chemotherapy in the Treatment of Low-grade Gliomas]

The standard postsurgical options for low-grade gliomas include watchful waiting or radiotherapy depending on the risk factors for recurrence. The use of chemotherapy for the treatment of this disease is generally controversial, although the recently published results of the first of two large randomized phase III clinical trials (RTOG 9802 a EORTC 22033-26033), focusing on the evaluation of chemotherapy for the upfront treatment of newly diagnosed low-grade gliomas, are reassuring in this respect. The long-term results of a RTOG 9802 comparing radiotherapy alone with radiotherapy and six cycles of adjuvant PCV chemotherapy (procarbazine, lomustine, vincristine) in patients with high-risk low-grade gliomas will probably have an impact on daily clinical practice. The increase in median overall survival from 7.8 years to 13.3 years, mainly for patients with oligodendrogliomas, is unprecedented, but the toxicity of PCV is too high and molecular marker analysis remains inadequate. It is still unclear whether less toxic temozolomide can replace PCV and whether temozolomide can be used upfront alone instead of with radiotherapy. This question is addressed by the ongoing EORTC 22033-26033 study. The preliminary results show no significant difference in progression-free survival between patients receiving radiotherapy and those receiving temozolomide alone. Treatment with temozolomide was not associated with an improvement in cognitive function compared with treatment with radiotherapy. Despite limited follow-up, the study clearly confirmed the importance of molecular characterization of low-grade gliomas, as currently defined in the new 2016 WHO Classification of Tumors of the Central Nervous System.

The aim of the review is to summarize available information from listed key clinical trials of chemotherapy for low-grade gliomas and draw attention to unresolved issues concerning the use of chemotherapy for the treatment of this disease.Key words: glioma - astrocytoma - chemotherapy - PCV - temozolomide - RTOG 9802 This work was supported by MH CZ - RVO (MMCI, 00209805) and by project of the Ministry of Education, Youths and Sports of the Czech Republic CEITEC 2020 (LQ1601). The authors declare they have no potential conflicts of interest concerning drugs, products, or services used in the study. The Editorial Board declares that the manuscript met the ICMJE recommendation for biomedical papers.Submitted: 21. 2. 2017Accepted: 20. 3. 2017.