Radiotherapy of glioblastoma

Abstract

Glioblastoma is the most common primary malignant brain tumour in adults with dismal prognosis. The current standard therapy includes maximal safe surgical resection followed by a combination of a concomitant radio/chemotherapy (temozolomide) and a long time temozolomide therapy after completion of radiotherapy. The aim of modern radiotherapy is to improve the conformity of the high-dose region with respect to the tumour while decreasing dose administered to surrounding normal tissue and avoid local necrosis and other long-term sequel based on the combined treatment. Modern radiotherapy planning of glioblastoma relies on three-dimensional conformal technique based on MRI and CT fused data sets. Treatment schemes include dosage of 60 Gy given in 2 Gy daily fractions. Hypo-fractionated radiation schemes may be used in patients with a low performance index. Other techniques such as stereotactic radiosurgery (RS) and brachytherapy have not been be beneficial and are not recommended in the routine management of newly diagnosed glioblastoma. With the beginning of the Temozolomide era, the survival time of some of the patients with glioblastoma improved; however the risk of pseudoprogression has increased due to a postulated radio sensitizing effect of this drug. To improve radiotherapy techniques follow-up will become more important to learn about the post-treatment effects in the treated tissue.