[The first experience in interstitial brachytherapy for primary and metastatic tumors of the brain].

ABSTRACT

In 2001-2002, the authors performed a course of brachytherapy in 15 patients with inoperable primary, recurrent, and metastatic brain tumors. The histostructural distribution was as follows low-grade astrocytoma (grade II according to the WHO classification) in 2 patients, anaplastic astrocytoma (AA) in 3, glioblastoma multiforme (GBM) in 5. Five patients had solid tumor deposits in the brain. Computer tomographic (CT) and magnetic resonance imaging (MRI) data were used to define a path for forthcoming biopsy and implantation at a "Stryker" navigation station, by taking into account the anatomy of the brain, vessels, and functionally significant areas. After having histological findings, plastic intrastats whose number had been determined by the volume of a target were implanted into a tumor by the predetermined path. Dosimetric planning was accomplished by using CT and MRI images on an "Abacus" system. The final stage involved irradiation on a "GammaMed plus" with a source of 192Ir. Irradiation was given, by hyperfractionating its dose (3-4 Gy twice daily at an interval of 4-5 hours) to the total focal dose (TFD) of 36-44 Gy. Patients with gliomas untreated with radiation also underwent external radiation in a TFD of 54-56 Gy and patients with brain metastases received total external irradiation of the brain in a TFD of 36-40 Gy. The tolerance of a course of irradiation was fair. In patients with AA and GBM, one-year survival was observed in 66 and 60%, respectively; in those having metastasis, it was in 20%. Six patients died from progressive disease. All patients with low-grade astrocytoma and one patient with anaplastic astrocytoma were alive at month 24 after treatment termination. The mean lifespan of patients with malignant gliomas and solid tumor metastasis was 11.5 and 5.8 months, respectively. Brachytherapy is a noninvasive and tolerable mode of radiotherapy that increases survival in some groups of patients with inoperable brain tumors.