Patient With Post-operative Recurrent Pancreatic Cancer Treated With Cone Beam Computed Tomography-Guided Stereotactic Adaptive Radiotherapy: A Case Report.

CT-guided adaptive radiotherapy (ART) for the treatment of pancreatic adenocarcinoma is rapidly increasing and has been shown to provide advanced treatment tools comparable to magnetic resonance imaging (MRI)-guided adaptive therapy. Here, we provide the first case report of a local pancreatic recurrence treatment after definitive resection using cone beam computed tomography (CBCT)-guided ART (CT-guided ART) enabled by HyperSight imaging (Varian Medical Systems, Inc., Palo Alto, CA, USA) for daily delineation of organs-at-risk (OARs) and target to improve the quality of online ART. A 61-year-old female was diagnosed with pancreatic adenocarcinoma, and her CT demonstrated a 1.9 cm lesion abutting the superior mesenteric vein. She received nine cycles of neoadjuvant mFOLFIRINOX, followed by a Whipple resection, with surgical pathology showing moderate to poorly differentiated adenocarcinoma and negative margins and perineural invasion. Approximately 3.5 months after resection, she was noted on endoscopic ultrasound to have a 1.7 cm lesion near the superior mesenteric artery and was referred to radiation oncology for treatment of local recurrence. She had adaptive stereotactic body radiotherapy to this lesion at 50 Gy in five fractions on the Ethos (Varian Medical Systems, Inc., Palo Alto, CA, USA). This case report highlights the utility of HyperSight CBCT for OAR and tumor delineation for the treatment of a patient with post-operative recurrent pancreatic cancer using CT-guided ART.