**4. Clinical characteristics**

The clinical presentation of GBM is, as intuited, dependent in large part on the location of the tumor. Continuing to bode ill for both treatment and prognosis is the sobering fact that malignant gliomas, and GBM in particular, grow insidiously and largely asymptomatically until they are big enough to elicit symptoms by sheer mass effect. By that time, tellingly, the options for surgical resection are relatively limited given extension into vital CNS parenchyma. Common presenting symptoms include recalcitrant headaches, unprovoked new-onset seizures, unprecedented memory loss, unaccountable changes in personality or consciousness, cognitive/language impairments, and other miscellaneous symptoms, i.e. nausea/vomiting. Though there are no pathognomonic symptoms that may help the clinician to reliably distinguish between the two WHO Grades of malignant gliomas, there have been cohort studies done that have shown some nuances in symptomatology between Anaplastic

Astrocytoma and Glioblastoma Multiforme (See Table 3). Prognostic factors boding favorably for patients diagnosed with malignant gliomas include a lower tumor grade, resection of tumor mass, younger age (less than 50 years) at time of diagnosis, higher performance status (e.g. ECOG) score and intact neurological function [35].


**Table 3.** Initial Symptoms in 565 Patients with Grade III or Grade IV Malignant Glioma (Data from Glioma Outcomes Project [29])
