Radiation and Chemotherapy for Brainstem Tumors

Gliomas originating in the brainstem are a heterogeneous group of tumors that can differ significantly in biology and prognosis. Despite recent insights into the biology of the most common brainstem glioma, diffuse intrinsic pontine glioma (DIPG), the standard treatment for brainstem gliomas has not changed significantly in nearly five decades. Radiation therapy is the mainstay of treatment for DIPG and other malignant brainstem gliomas, and is the only modality that improves outcomes for these tumors. While chemotherapy may have some utility for non-DIPG brainstem tumors, no chemotherapeutic agent has demonstrated significant efficacy within a clinical trial for children with DIPG. Diffuse brainstem gliomas in adults appears to have different biology, and adjuvant chemotherapy may have modest efficacy against adult malignant brainstem glioma. However, the prognosis for all patients with diffuse malignant brainstem gliomas remains dismal. Nevertheless, the recent distinction of DIPG as a unique clinical entity, development of tools such as cell lines and animal models to perform disease-specific pre-clinical studies, insight into its biologic underpinnings such as epigenetic dysregulation, and research to overcome defined obstacles to drug delivery have laid the groundwork for the development of novel, directed, disease-specific approaches that hold promise.