[Radiotherapy of adult glial tumors: new developments and perspectives]

Adult gliomas (WHO grade II, III and IV) are heterogeneous primitive brain tumors. The prognosis of these tumors depends on multiple factors such as age at diagnosis, Karnofsky score, histopathology, biology and treatments. Radiotherapy (RT) plays an important role in the treatment strategy, after surgery. RT has been evaluated in terms of survival, median time to progression and toxicity. Techniques of RT have improved, during the last two decades: neuro-imaging (CT-scan, MRI and PET) and dedicated computers for dosimetry make it possible to deliver an homogeneous dose in the target volume while sparing normal tissues. Photons X are usually delivered with stereotactic or conformational noncoplanar techniques. Total doses delivered range from 50.4 to 60 Gy (1.8-2 Gy/fraction). Median survivals are different with regard to the tumor grade. However, genetic and biological factors also are important prognostic factors such as inactivation of the MGMT gene for glioblastomas and loss of heterozygosity (LOH) 1p/19q, usually associated with pure oligodendroglioma. During the 1990s, temozolomide (TMZ) was specifically developed as a chemotherapy agent against primary brain tumors. The current TMZ/RT regimen in newly diagnosed GBM has been proposed as a standard treatment. The optimal treatment strategy is not known. New clinical trials are needed to assess new techniques of RT; a further improvement in medical treatment requires novel agents.