Adult brain tumors

Radiotherapy plays an important role in the management of adults with brain tumors. This refresher course will focus on a wide variety of benign and malignant brain neoplasms and how contemporary radiotherapy affects survival. In each case the intent of radiation therapy is to destroy the neoplasm without affecting normal tissues. However, for many neoplasms serial post-treatment scans may show little change, and success is often measured more by absence of tumor progression than by scan normalization. Successful outcome after radiation therapy of brain tumors usually requires that (1) there is no tumor extension beyond the target volume, (2) adequate dose is delivered to the target volume, and (3) normal tissue tolerance doses are not exceeded. For some tumors it may be impossible to satisfy all three criteria. Three-dimensional treatment planning based on MRI or CT makes it possible to guarantee delivery of the full dose of radiation to gross tumor while minimizing the volume of normal tissue receiving high dose. Acceptable dose conformity can often be achieved with 2-4 static beams or arcs and are usually preferable to opposed lateral fields. Examples of planning solutions for a variety of tumor types, sizes, and anatomic location will be given. For some tumors, protocols involving substantial dose escalation require a large number of non-coplanar x-ray beams or particle therapy. Several concepts and techniques which relate to the treatment of brain tumors will be discussed, including conformal radiotherapy, brachytherapy, radiosurgery, fractionated stereotactic radiotherapy, altered fractionation, inverse treatment planning, re-irradiation and biologically effective dose (BED)