Is chemotherapy alone an option as initial treatment for low-grade oligodendrogliomas?

Curr Opin Neurol. 2020 Dec;33(6):707-715. doi: 10.1097/WCO.0000000000000866.

Abstract

Purpose of review: The management of low-grade (grade II) oligodendrogliomas is still controversial, due to their rarity and long-term survival. According to recent WHO 2016 Classification of central nervous system tumors oligodendrogliomas are defined by the coexistence of molecular alterations, such as isocitrate dehydrogenase (IDH)1/2 mutations and 1p/19q codeletion. These tumors have better outcome and higher response to chemotherapy compared with diffuse astrocytomas.

Recent findings: The association of radiotherapy and procarbazine, lomustine (CCNU), vincristine chemotherapy in low-grade oligodendrogliomas is definitely superior over radiotherapy alone, and yields median progression-free survival and overall survival values exceeding by far 10 years. Chemotherapy alone yields results that are inferior compared with radiotherapy + procarbazine, CCNU, vincristine but may better preserve cognitive functions from radiotherapy-induced damage. Chemosensitivity of oligodendrogliomas is related to a high percentage of O6-methylguanine-DNA methyltransferase methylation and low expression of DNA repair genes. Recurrent defects in mismatch repair pathways may induce hypermutation and secondary resistance to temozolomide, but not to nitrosoureas.

Summary: Reoperation at progression following initial chemotherapy is increasingly adopted, thus allowing a further delay of radiotherapy. In the future targeting IDH1/2 mutations following incomplete surgery may represent a new innovative option.

Publication types

  • Review

MeSH terms

  • Antineoplastic Agents / therapeutic use*
  • Brain Neoplasms / drug therapy*
  • Humans
  • Lomustine / therapeutic use*
  • Oligodendroglioma / drug therapy*
  • Temozolomide / therapeutic use*
  • Treatment Outcome
  • Vincristine / therapeutic use*

Substances

  • Antineoplastic Agents
  • Vincristine
  • Lomustine
  • Temozolomide