Evidence-based adjuvant therapy for gliomas: current concepts and newer developments

The incidence of gliomas is increasing worldwide, including India. Of the 18,820 new cases of primary central nervous system (CNS) tumors diagnosed annually in the United States, gliomas account for over 60% with 30-40% of them being glioblastoma multiforme (GBM), 10% being anaplastic astrocytoma (AA), and 10% being low grade gliomas (LGGs). This is in contrast to one study from West Bengal, India, in which only 7.9% of the brain tumors were GBMs, while 46.8% were astrocytomas. Of all adult primary CNS tumors, GBM is the most common and the most malignant with about 7,000 to 8,000 new cases annually in the United States. Given poor outcomes, a number of treatment approaches have been investigated. Common to these approaches is the use of adjuvant radiation therapy, even as surgery alone, with or without chemotherapy, may be the mainstay for some lower grade and low-risk gliomas. Today, treatment typically involves external beam radiation, with concurrent and adjuvant chemotherapy for more aggressive histologies. Although gliomas are relatively uncommon, active research is ongoing. Results of landmark trials along with some of the recently published trials are presented. These trials and management strategies as well as evolving concepts are found by reviewing over 200 articles in the National Library Medical (NLM) database, PubMed, more than 60 of which are refrenced. Specifically, the database is searched using the following keywords, with various combinations: glioma, low-grade, anaplastic, astrocytoma, oligodendroglioma, oligoastrocytoma, glioblastoma multiforme, chemotherapy, radiation, new concepts, phase III, MGMT, CDX-110 (Celldex), temozolomide, 1p/19q deletion, and bevacizumab.