Intraoperative 32P High Dose Rate Brachytherapy of the Dura for Recurrent PRIMARY and Metastatic Intracranial and Spine Tumors
Folkert, Michael R. M.D., Ph.D.; Bilsky, Mark H. M.D.; Cohen, Gil’ad N. M.S.; Zaider, Marco Ph.D.; Dauer, Lawrence T. Ph.D.; Cox, Brett W. M.D.; Boland, Patrick J. M.D.; Laufer, Ilya M.D.; Yamada, Yoshiya M.D.
Treatment of spine and intracranial tumors with dural involvement is complicated by radiation tolerance of sensitive structures, especially in the setting of prior treatment.
Objective: To evaluate if intraoperative brachytherapy with short-range sources allow therapeutic dose delivery without damaging sensitive structures.
Methods: Prior treatment median doses (range) were 3000 cGy (1800-7200 cGy) for 8 primary/recurrent and 17 metastatic spine patients and 5040 cGy (1300-6040 cGy) for 5 locally recurrent and 2 metastatic intracranial patients. Patients underwent gross total or maximal resection of the tumor and were then treated with an intraoperative brachytherapy plaque consisting of a flexible silicone film incorporating 32P. 1000 cGy was delivered to 1 mm depth; percent depth-dose is <1% at 4 mm from prescription depth. Post-operative radiation median dose of 2700 cGy (1800-3000 cGy) was delivered to 15 spine patients and 3000 cGy (1800-3000 cGy) to 3 intracranial patients. Median follow-up was 4.4 months (range 2.6-23.3) for spine patients and 5.3 months (range 0.7-16.2) for intracranial patients.
Results: At 6 months follow-up, for all spine patients, local progression-free survival and overall survival were both 83.3% (95% CI: 62.3%-94.3%); for all intracranial patients, local progression-free survival was 62.5% (95% CI: 23.8%-90.9%) and overall survival was 66.7% (95% CI: 26.7%-92.9%). There were no intraoperative or postoperative complications secondary to radiotherapy.
Conclusion: Use of the 32P brachytherapy plaque is technically simple and not associated with increased risk of complications, even after multiple radiation courses. Local control rates are >80% in patients with proven radioresistant disease in the spine.
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