Neoadjuvant stereotactic body radiation therapy (SBRT) for borderline resectable pancreas cancer: Moffitt Cancer Center initial experience.

Abstract

302 Background: Our institution has reported a strategy of using neoadjuvant GTX (gemcitabine, docetaxel, and capecitabine) chemotherapy followed by 5FU-based intensity-modulated radiation therapy (IMRT) for borderline resectable pancreas cancer. We now report our early experience with induction chemotherapy followed by stereotactic body radiation therapy (SBRT). Methods: This retrospective review evaluates our initial 5 fraction SBRT experience in 15 patients following induction chemotherapy for borderline resectable pancreatic cancer. Staging included pancreatic protocol CT, endoscopic ultrasound, and PET/CT scan. Induction regimens consisted of GTX for 3 cycles in 12 patients and gemcitabine alone in 3. Daily SBRT was delivered to the pancreas at least 1 week after completing systemic chemotherapy. Endoscopically implanted fiducial markers and daily cone beam CT were used for image guidance. Treatment was delivered on a Varian Trilogy unit using 6-15 MV photons. Doses were selected based on dose painting the portion of tumor adjacent to the vasculature to a higher dose while meeting normal tissue constraints. The entire gross tumor received a dose of 5-6 Gy per fraction while the portion of the tumor adjacent to the vasculature resulting in the borderline designation received up to 8 Gy per fraction. Patients were re-imaged 3-4 weeks after SBRT for consideration of surgery. Results: There were no acute or late grade 3 toxicities. At the time of this analysis, not all treated patients have reached the restaging time point, but 9 of 15 (60%) were candidates for resection. Six patients have gone to resection with negative margins and without any increased complications. Two patients were found to have disease surrounding the vasculature preventing resection. One patient had cardiac issues at surgery and resection was aborted. One patient was explored and found to have liver metastases. Conclusions: Integration of SBRT in conjunction with systemic therapy is well-tolerated and appears to facilitate margin-negative resection in borderline resectable pancreatic cancer. No significant financial relationships to disclose.