Phase II Study to Evaluate the Efficacy of Trilogy Stereotactic Radiosurgery for Pancreatic Cancer

In this study, we propose to combine stereotactic body radiotherapy (SBRT) with standard gemcitabine chemotherapy. We hypothesize that earlier administration of systemic chemotherapy may prolong the interval to distant progression and improve overall survival in these patients. In this study, we will treat pancreatic cancer patients with locally advanced disease with 3 weeks of gemcitabine, followed by Trilogy(TM) SBRT and additional gemcitabine. 30 patients will be accrued to this study at Stanford University Medical Center, the only site participating in this research study. Treatment on this protocol requires placement of 3-5 gold (99.9% pure) fiducials for targeting purposes. Four to 7 days after placement of the fiducials, patients will then undergo a 4D pancreatic protocol CT scan through the upper abdomen. In addition, an FDG PET scan is required for treatment planning purposes. This imaging set will be processed for radiosurgery, using a modified linac based radiation treatment planning system (EclipseTM). An SBRT treatment plan will be developed based on tumor geometry and location. All patients will receive a single fraction of 25 Gy prescribed to the isodose line that completely surrounds the gross pancreatic tumor volume (GTV) as defined by the contrast CT. Following SBRT, patients will be monitored clinically and radiographically.