Brachytherapy: Results of two different therapy strategies for patients with primary glioblastoma multiforme.
BACKGROUND
In the current study, the authors describe and compare two different strategies of brachytherapy for the treatment of patients with primary glioblastoma multiforme (GBM).


METHODS
The study was comprised of 84 patients. Forty-five patients were implanted with permanent or temporary low activity iodine-125 ((125)I) seeds in Cologne and 21 patients were implanted with temporary iridium-192 ((192)Ir) wires in Amsterdam. Both groups received external beam radiation therapy (EBRT); the (125)I group received 10-30 grays (Gy) with the implant in situ and the (192)Ir group received 60 Gy before implantation. In Cologne, implantation was performed after a diagnostic stereotactic biopsy whereas in Amsterdam implantation took place after cytoreductive diagnostic surgery. In addition, 18 patients in Amsterdam served as a control group. This group received only EBRT after cytoreductive surgery.


RESULTS
In both groups the mean age of the patients was between 50-55 years, with 80% of the patients age > 45 years. The mean implantation volume encompassed by the referenced isodose was 23 cm(3) for (125)I and 48 cm(3) for (192)Ir. Initial dose rates were 2. 5-2.9 centigrays (cGy)/hour for permanent (125)I, 4.6 cGy/hour for temporary (125)I, and 44-100 cGy/hour (mean, 61 cGy) for (192)Ir. A total dose of 50-60 Gy, 60-80 Gy, and 40 Gy, respectively, was administered at the outer margins of the tumor. The median survival was approximately 16 months for both the (125)I group and the (192)Ir group. This was 6 months longer than the median survival in the control group. Reoperations were performed in 4 patients in the (125)I group (9%) versus 7 patients in the (192)Ir group (33%). No complications or late reactions were reported in the (125)I group, whereas one case of hemorrhage and three cases of delayed stroke were observed in the (192)Ir group.


CONCLUSIONS
The equal median survival times in these two brachytherapy groups with such different dose rate radiation schedules support the hypothesis that dose rate does not play a major role in the survival of patients with primary GBM.
Koot
R W
RW
Department of Neurosurgery, Academic Medical Center, Amsterdam, The Netherlands.
Maarouf
M
M
Hulshof
M C
MC
Voges
J
J
Treuer
H
H
Koedooder
C
C
Sturm
V
V
Bosch
D A
DA
D000328:Adult; D000368:Aged; D001918:Brachytherapy / Q000009:adverse effects / Q000379:methods*; D001932:Brain Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D002543:Cerebral Hemorrhage / Q000209:etiology; D005260:Female; D005909:Glioblastoma / Q000473:pathology / Q000532:radiotherapy*; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use; D007496:Iridium Radioisotopes / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D016019:Survival Analysis; D016896:Treatment Outcome
D007457:Iodine Radioisotopes; D007496:Iridium Radioisotopes