Treatment of spine and intracranial tumors with dural involvement

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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