[Patterns of recurrence in malignant gliomas after brachytherapy].

More than 80% of malignant gliomas have been reported to recur locally after conventional chemoradiation therapy. This regional pattern of recurrence has encouraged the introduction of new treatments for local tumors. Since 1987 interstitial brachytherapy using Iridium-192 seeds has been carried out in our department for malignant brain tumors. The present study was designed to evaluate the patterns of recurrence following interstitial brachytherapy and to assess how this recurrence differs from that observed in patients treated by conventional means. Ten patients who satisfied the following criteria were selected among 41 patients treated with brachytherapy. The criteria were; 1) histologically diagnosed to be malignant glioma (astrocytoma grade III or glioblastoma), 2) followed up with MRI every month after the brachytherapy, 3) follow-up period was more than 6 months, and 4) the time of recurrence was confirmed. The patients were classified into 3 groups according to the patterns of tumor recurrence as follows; 1. Local recurrence group: The tumor recurred near the pretreatment tumor site. 2. Necrotomy group: Reoperation was performed because of neurological deterioration and radiographic evidence of increasing mass effect with surrounding edema. Neurological symptoms were unchanged or improving during the 6 months after the reoperation. 3. CSF seeding group: Primary tumor was well controlled, but seeding via cerebrospinal fluid was recognized on MRI. Local recurrence occurred in three patients, necrotomy was carried out in three patients, and CSF metastases were defined by both MRI and clinical symptoms in four patients. Median radiation does was 33 Gy in the local recurrence group, 57.6 Gy in the necrotomy group, and 43.2Gy in the CSF seeding group.(ABSTRACT TRUNCATED AT 250 WORDS)