Radiosensitizers in Brain Cancer

Abstract

Primary brain tumors and brain metastases from solid tumors are usually associated with poor prognosis and impairment in quality of life. The poor prognosis is mainly due to the limited efficacy of available treatment modalities. Standard palliative treatment in patients with multiple brain metastases consists of corticosteroids and cranial irradiation, e.g. whole brain radiation therapy. Whole brain radiotherapy will relieve symptoms and temporarily improve neurologic deficits in the majority of patients. However, evaluations of a large database by the Radiation Therapy oncology Group indicate that the prognosis for patients with brain metastases remains poor, with a median survival between 4 and 7 months. The median survival of patients with glioblastoma, the most frequent primary brain tumor in adults, is generally <1 year from the time of diagnosis. Standard therapy in patients with primary brain tumors consists of surgical resection to the extent that is safely feasible, followed by radiation therapy and commonly adjuvant chemotherapy. Treatment strategies developed over the past decades for patients with brain metastases and primary brain tumors remain inadequate, although they have slowly improved outcomes. Interest exists in using combined chemotherapy and radiation therapy, as well as the combination of a radiosensitizer and radiotherapy. Novel radiosensitizers, such as efaproxiral and motexafin gadolinium have shown potential and are under investigation. A multimodal approach can improve local control and overall survival, as well as reducing treatment-related adverse effects.