Does Post–Neoadjuvant Therapy PET Response Predict Pathologic Outcomes in the Treatment of Sarcomas?

sarcomas (10), and other malignancies (2). 4 of these patients had radiation associated sarcomas within prior radiation field for different malignancies. Materials/Methods: The median age of the patients at diagnosis was 51 (range 7-75). The patients were treated from Feb, 2000 to Oct, 2013. 6 patients were treated with dural plaques during both stages of planned 2-stage operations. 46 patients were planned for treatment during one of the staged resection. The types of plaques used included Y-90, P-32 and Ir-192. Median dose was 10 Gy (range 7.5 e 17 Gy) prescribed to the dural surface in a single fraction. The median length of the dural plaque is 36mm, and the median arc of the dural plaque is 153 . All patients had also received preand/or postoperative photon/proton external beam radiation therapy. We limit spinal cord dose to 63/54 Gy RBE to surface/center. Results: In 7 of 51 patients, dural plaque brachytherapy was not given (4 because of intraoperative anatomic constraints, and 3 because of dural tears). Results are based on intention to treat analysis. The median follow up time from date of planned dural plaque brachytherapy is 17.7 months. Of the 3 patients treated for primary disease and had local recurrence, 2 presented with radiation associated sarcoma, which significantly limited their external beam radiation dose. No acute or late myelopathy could be attributed to dural plaque brachytherapy. 6 patients had intraoperative dural tear (none directly caused by plaque placement). In 3 of these 6 patients, dural plaque treatments were given. In 1 of the 3 patients, a persistent CSF leak developed postoperatively, and it eventually resolved without intervention. Conclusions: Dural plaque brachytherapy allows high dose of radiation to be safely delivered to the dural surface. Dural plaque shall be considered in situation when tumors are in close proximity to spinal cord, and sufficient dose of radiation cannot be delivered with external beam radiation therapy alone. Author Disclosure: D.D. Yip: None. T.F. DeLaney: None. A. Jacobson: None. F.J. Hornicek: None. J.H. Schwab: None. T.C. Mauceri: None. Y. Chen: None.