AT-10SURGERY (S) AND PERMANENT INTRAOPERATIVE BRACHYTHERAPY (BT) IMPROVES TIME TO PROGRESSION OF RECURRENT INTRACRANIAL NEOPLASMS: A REPORT OF 27 CASES USING A MODULAR, BIOCOMPATIBLE CARRIER AND REAL-TIME DOSIMETRIC PLANNING

BACKGROUND: We report our experience using surgery (S) and permanent brachytherapy (BT) implants in the treatment of 27 separate recurrent/progressive intracranial neoplasms in 20 adult patients, all of whom had progressed despite prior standard of care treatment. Tumors treated: Grade II meningioma (9), Grade III meningioma (5), metastases (7), high grade glioma (4), craniopharyngioma (1) and dural sarcoma (1). Prior same site surgeries: mean 2, range 0-4. Prior same site RT courses: mean 2, range 1-3. Prior cumulative radiation dose: mean 70.5 Gy, range 50-89 Gy. METHODS: All patients underwent resection and intraoperative BT utilizing a modular-design biocompatible radiation-source carrier and Cs-131 in seed form. The modular geometry of the carrier, with placement under direct visualization, enabled real-time dosimetry with 60 Gy at 5 mm depth utilized for all cases. Cox's proportional-hazards model was used to model the effect of BT, with each tumor serving as its own control. RESULTS: Median progression-free survival (PFS) for prior treatment was 5.8 months (range 1-27 months). Following S + BT, only one patient, with chondrosarcoma, has progressed in the treated area (after 5 months). Thus, median PFS has not been reached for S + BT (follow-up range 0.13-21.5 months; hazard ratio 0.05, p < 0.0001, log-rank test). Time added to surgery averaged 20 min. Mean number of seed sources used was 21 (range 4-41); mean implanted mCi 101 (range 9-228). One tumor bed had clinically silent, biopsy proven radiation necrosis. No other patient has had symptomatic or asymptomatic necrosis. 8 patients have died: 5 of intracranial progression away from the treated area(s), 2 from extracranial causes, and 1 post-op death unrelated to the implant. CONCLUSION: Resection and precise intraoperative BT made possible by the carrier design demonstrate excellent early results in this ongoing, IRB approved trial for patients with recurrent intracranial neoplasms.