Primary brain tumors: Characteristics, practical diagnostic and treatment approaches

Primary brain tumors are classified according to the tissue of phylogenic origin. Tumors arising from the neuroepithelium encompass a subgroup of neoplasms collectively referred to as Gliomas. Of this subgroup; astrocytomas are by far the most common. Astrocytomas are further subdivided by a four tier grading system based on The World Health Organization (WHO) classification where Grade I tumors represent the most benign and am enable to cure by surgical resection. Grade II astrocytomas are more infiltrative, but less aggressive than their more malignant counterpart Grades III and IV. However, due to their infiltrative nature grades II-IV are not cured by surgical extirpation. The most frequently used treatment regimen for malignant primary brain tumors include surgery for debulking or biopsy followed by postoperative radiation that is often combined with chemotherapy followed by 6 months of adjuvant chemotherapy. When paired with improved imaging and diagnostic modalities as well as new anti-angiogenic and molecular targeted therapies, the outcome for patients newly diagnosed with a malignant glioma has improved considerably. In addition, cancer stem cell research offers insight into the biology and pathogenesis of primary brain tumors. Currently, many studies implementing angiogenesis inhibitors and biologic modifiers offer encouragement for more patient participation in well-designed clinical trials for those patients who are eligible.