Glioblastoma

Clinical Manifestations. As discussed above, signs and symptoms of underlying glioblastomas reflect the location of the tumor and its rate of growth. Because of the rapid rate of growth, symptoms tend to be of shorter duration before diagnosis. The most frequent presenting symptoms are headache and seizures.

Diagnostic Studies. On MRI, glioblastomas commonly present with heterogeneous or ring-like enhancement admixed with central areas of necrosis. Fluid attenuated inversion recovery (FLAIR) and T2-weighted MRI images illustrate infiltrative tumor and surrounding edema, which is often significant. If MRI is contraindicated, CT with and without contrast is acceptable, although the anatomy is less defined.

Treatment. Treatment of glioblastomas is multimodal, involving surgery, radiation, and chemotherapy. Initial neurosurgical resection allows for definitive diagnosis, alleviation of neurologic symptoms, and debulking, which can improve outcome. After surgery, patients undergo radiation in combination with chemotherapy. External beam radiation has been shown to be the single most effective treatment for glioblastomas and other high-grade gliomas. The addition of temozolomide, a chemotherapy agent, has been shown to significantly extend survival. Despite combined therapy, the tumors almost inevitably recur and progress. Prognostic factors associated with increased survival include younger age, higher performance status, greater extent of resection, as well as some genetic factors, such as the presence of the deoxyribonucleic acid (DNA) repair enzyme O6-methylguanine–DNA-methyltransferase or isocitrate dehydrogenase (IDH1) mutation. Experimental therapies targeting angiogenesis (the formation of new blood vessels from preexisting adjacent vessels) have emerged as novel anticancer agents. For example, bevacizumab, a humanized monoclonal antibody to vascular endothelial growth factor (VEGF) was granted accelerated approval by the Food and Drug Administration (FDA); however, its effect on survival remains modest. Much current research has focused on the development and use of small molecule inhibitors to target molecular signaling pathways implicated in tumorigenesis.

In addition to treatment of tumor growth, symptomatic treatment is equally as important. Corticosteroids are often used to relieve the surrounding edema. Antiepileptic agents are only necessary when patients suffer from seizures.

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