Intracranial Tumors

Abstract

The role of radiation therapy in tumors of the central nervous system is well known, and in most tumor types it is an important modality in the overall therapeutic strategy. (Karlson and Brady 1987). In the case of primary tumors of the central nervous system the most frequent cause of treatment failure is local recurrence. Therefore, there is a need to improve the use of local treatment modalities such as surgery and radiation therapy, or the combination of both. The conventional treatment of high grade astrocytomas has combined surgery and brain irradiation, as well as including chemotherapy with nitrosureas (Levin et al. 1989). This histologic subtype is the most frequent brain tumor, and the final treatment results have reached a plateau since the last decade. Multi-institutional randomized trials ex-variations in chemotherapy regimes and radiotherapy schemes, have constantly reported median survival times of around 12 months, with a small proportion of patients displaying long-term survival (Shapiro 1 9 8 6). An important feature of prospective trials has been the identification of favorable prognostic factors in patients with high grade astrocytoma, such as an age of less than 40 years, the histologic subtype anaplastic foci astrocytoma, and excellence of surgery (Nelson etal. 1982).