Malignant gliomas are the most frequent cancers originating from the central nervous system. Glioblastoma multiforme (GBM) (World Health Organization (WHO) grade IV) is the most common and biologically aggressive subtype. It is a highly aggressive tumour with a dismal prognosis.

Systemic cytotoxic treatment has been playing an increasing important role in improving the outcome of high grade glioma . Older generation of chemotherapy, mostly comprising of nitrosureas as the backbone chemotherapy regimen, has resulted in a significant, albeit modest, increased overall median survival of patients with high grade glioma. The addition of temozolomide administered concurrently with radiation therapy (RT) followed by adjuvant temozolomide has improved the survival of GBM patients.Many novel systemic therapies had been subjected to vigorous clinical trials testing over the past decade, particularly the anti-angiogenic agents. The rapidly evolving field of immunotherapy will hopefully improve the current therapeutic modalities in the treatment of high grade glioma.

With the increasing usage biologic agents, particularly the anti-angiogenic agents, and immunotherapy, assessing the tumour response to treatment will be challenging as the current available application is far from ideal.