The pancreas is an organ located behind the stomach. It produces enzymes that digest food and hormones that regulate blood sugar levels. Cancer of the pancreas is the fourth leading cause of cancer death in the United States. Pancreatic cancer is often difficult to diagnose, and surgical removal of the tumor is the only chance for cure. Unfortunately, many pancreatic tumors spread to lymph nodes, blood vessels, or other tissues before they are diagnosed. These tumors, which cannot be removed entirely by surgery, are called “unresectable.”