Surgery

Tumors are often treated surgically. Regardless of surgical approach, surgery provides tissue for accurate diagnosis and evaluation for possible adjuvant therapy. Surgery also is indicated to decrease seizure activity and potentially decrease the need for AEDs and the risk of sudden unexpected death.98,99

The pathology of the lesion is the most important prognostic factor. When radiologic studies fail to determine the nature of the lesion, a biopsy may be necessary. Adjunctive therapies such as chemotherapy, radiation therapy, or both are often considered following surgery, especially for aggressive histologies.

Surgical risks are determined by lesion location, its proximity to eloquent cortex, and the involvement of vascular structures and nerves. The patient’s medical condition is yet another important factor to consider. Severe cardiopulmonary or organ-system disease may be a contraindication to general anesthesia.

In treating children, early surgical intervention may permit the developing brain of the young child to recover quickly and maximize plasticity.

Nonsurgical treatment

Some tumors are best treated by observation for progression. Other tumors, such as those in deep subcortical regions, may be surgically inaccessible. Nonsurgical treatment of brain tumors can include chemotherapy, radiation, or radiosurgery.

Chemotherapy

Chemotherapeutic options include local agents applied directly on the tumor bed, or systemic intravenous agents. To control local tumor recurrence or progression in a tumor bed, surgeons may implant agents such as iodine-125 seeds or bischloroethyl-nitrosourea biodegradable wafers.69–72 Theoretical advantages to such therapy include direct delivery of high concentrations of drug or radiation to the tumor bed and increasing penetration into surrounding tissue.

Systemic chemotherapy may increase both survival and quality of life. Temozolomide, for example, an oral cytotoxic alkylating agent that methylates guanine, has been beneficial in clinical trials to treat recurrent glioblastoma multiforme.73 In a study of 225 patients, temozolomide delayed disease progression for a median of 12 weeks and led to 6-month survival of 60%, compared to only 44% for patients given procarbazine.74 In treatment for recurrent anaplastic astrocytomas, it was well tolerated, with a progression-free survival of 5.4 months and an overall median survival of 13.6 months in a group of 109 patients.75

Radiation

Cranial irradiation may reduce seizures in patients with unresected, partially resected, or recurrent tumors.47,100,101 Acutely, however, cranial irradiation may worsen seizure control.

Radiosurgery

Stereotactic radiosurgery (SRS) allows a radiation beam to be maximally and precisely focused on the tumor, with sparing of surrounding normal brain tissue. Since its inception by Lars Leskell in 1951, radiosurgery has evolved significantly. Under specific circumstances, it can be used to treat benign, malignant, and metastatic tumors of the brain, as well as vascular malformations. Several studies have recently suggested a use of this therapy for treating lesional and nonlesional epilepsy.76–80 The role of radiosurgery and its use with other treatment modalities remains to be further clarified.

Adapted from: Mangano FT, McBride AE, and Schneider SJ. Brain tumors and epilepsy. In: Ettinger AB and Devinsky O, eds. Managing epilepsy and co-existing disorders. Boston: Butterworth-Heinemann; 2002;175–194.
With permission from Elsevier (www.elsevier.com). 

I<