[Interstitial brachytherapy for malignant gliomas using the Brown-Roberts-Wells (BRW) stereotactic system]

Eleven patients harboring recurrent or deep-seated malignant gliomas were treated by interstitial brachytherapy with 192Ir seed assembly, between June 1987 and September 1989. Implantations for the afterloaded catheter were performed using the Brown-Roberts-Wells (BRW) CT guided stereotactic system. The number of seeds and the distribution of the implants were chosen in such a way that the minimum tumor dose of 30-50Gy could be delivered to the surface or 1cm beyond the rim of the contrast enhancement. The radioactive sources were held in the afterloaded catheters that were removed after the desired dose had been delivered. Response to therapy was measured by serial CT scans and clinical examination. Tumor regressions were seen by CT scans made 2 or 3 months after implantation. One tumor showed complete regression (CR), four showed partial response (PR), one showed minor response (MR) and 5 showed no change (NC). Overall response rate was 54%. Six patients died 3 to 18 months following implantation, and five are still alive 7 to 27 months after implantation. No complications such as infection or hemorrhage were observed during the treatment. A patient harboring large (6.5cm in diameter) recurrent glioblastoma in the rt. parietal robe required a craniotomy due to the mass growing for one and half month after implantation, and radiation necrosis of the entire tumor mass was documented. The technique of stereotactic interstitial implantation was clinically well tolerated and easily reproducible and our preliminary results seemed encouraging. Technical improvement to achieve an adequate isodose distribution to cover the tumor volume might lead to improved survival rates.