This synthesis of the literature on
radiotherapy for
brain tumors, ie,
cancer originating in the central nervous system (CNS), is based on 81 scientific articles, including 25 randomized studies, 13 prospective studies, and 25 retrospective studies. These studies involve 11,081 patients. A more comprehensive chapter on
brain tumors may be ordered from SBU. Curative treatment is not available for patients with highly
malignant glioma (grades III and IV). Postoperative
radiotherapy for highly
malignant glioma extends patients' survival, with good quality of life, by several weeks to several months. Virtually all patients die from this disease. Although the clinical benefits from
radiotherapy, measured as survival, appear to be modest, it is more effective than any
chemotherapy tested thus far. The clinical effects of
radiotherapy for highly
malignant glioma are improved only marginally by altering factors such as absorbed dose, fractionation, irradiated tissue volume, radiation quality, or by adding radiosensitizing substances.
Radiotherapy alone usually provides a clear but temporary improvement in patients with highly
malignant glioma, hence it clearly has a palliative benefit. Postoperative
radiotherapy for low-grade
malignant gliomas (grades I and II) may extend survival. It also reduces
tumor volume. No evidence shows that
radiotherapy alone or postoperatively can lead to cure. In patients who have undergone subtotal
meningioma resection, postoperative
radiotherapy substantially reduces the risk for recurrence and extends life, and is thereby indicated.
Radiotherapy is not indicated following macroscopic radical
meningioma surgery. Patients with
brain metastases experience rapid neurological improvement following
radiotherapy to the whole brain, and this palliative effect often remains throughout the remainder of the patient's life. Palliative
radiotherapy, often to large volumes of the CNS, is therefore motivated in a large proportion of the patient groups. In a smaller group of patients with solitary
metastases,
radiotherapy may be given postoperatively following radical neurosurgery. Life may be extended in this group, otherwise
radiotherapy does not influence survival. Stereotactic
radiotherapy of solitary, mainly spherical
metastases in the brain is often superior to other known methods with respect to palliation and survival. The number of patients is, however, relatively small.