Extraneural metastatic glioblastoma after interstitial brachytherapy

Purpose: This is a report of 3 cases of extraneural metastasis of glioblast oma after interstitial radiation and assessment of pertinent literature add ressing concern over an increased risk of these events with this therapy. Methods and Materials: In a series of 82 patients treated with I-125 brachy therapy for primary malignant brain tumors over a 7-year interval, 3 cases of extraneural glioblastoma were identified. The multicatheter technique fo r delivery of 125I sources was utilized in all. Extraneural metastases were documented by imaging studies or biopsy. Over the same period, 310 patient s with primary malignant brain tumors were treated without brachytherapy. Results: Biopsy-proven scalp and skull metastases occurred in 2 patients, a t 3 and 8 months following brachytherapy. Each developed radiographic evide nce of systemic metastases at 7 and 14 months postbrachytherapy, respective ly, The third patient developed biopsy-proven cervical node involvement 4 m onths after brachytherapy, No patients with malignant gliomas undergoing cr aniotomy or stereotactic biopsy, but not brachytherapy, during the same tim e period developed extraneural metastases, Incidence in previously reported series commenting on this otherwise rare process range from 0% to 4.3%, Th e incidence of extraneural metastases in this series is 3.7% (3/82) and is comparable to those reports. Conclusions: Percutaneous catheter-delivered brachytherapy may be associate d with an increased incidence of extraneural metastatic glioma. (C) 2000 El sevier Science Inc.