Brain tumor
Glioblastoma multiforme (GBM) is the most aggressive (grade IV) and most common form of a malignant brain tumor. Even when aggressive multimodality therapy consisting of radiotherapy, chemotherapy, and surgical excision is used, median survival is only 12–17 months. Standard therapy for glioblastoma multiforme consists of maximal surgical resection of the tumor, followed by radiotherapy between two and four weeks after the surgical procedure to remove the cancer, then by chemotherapy, such as temozolomide. Most patients with glioblastoma take a corticosteroid, typically dexamethasone, during their illness to relieve symptoms. Experimental treatments include targeted therapy, gamma knife radiosurgery, boron neutron capture therapy and gene therapy.
Glioma
Most glioblastomas are infected with cytomegalovirus, which speeds the development of tumors. Though some studies have shown that farmers have higher rates of gliomas compared to the general population, exposure to farm animals or manure is not associated with glioma. Later studies have not found an association between farming and gliomas; similar conflicting data concerns teachers and glioma. More consistent data shows that architects, surveyors, retail workers, butchers, and engineers have higher rates of gliomas. Most studies have found that pesticide exposure is probably not a cause of glioma, though a minority of studies have found an association.