Interventional endosonography for pancreatic cancer.

Endoscopic ultrasound (EUS) was initially developed in the early 1980s as a research tool to overcome limitations of transabdominal ultrasound for an examination of the pancreas caused by intervening gas, bone, and fat. Since its introduction into clinical practice, EUS has revolutionized the diagnosis and treatment of gastrointestinal disorders, particularly pancreatic cancer. The ability to position the transducer in direct proximity to the pancreas via the stomach and proximal duodenum, combined with the use of high-frequency ultrasound, provides detailed high-resolution images of the pancreas that are superior to those of computerized tomography and transabdominal ultrasound. The incorporation of fine-needle aspiration (FNA) technique has significantly improved the accuracy of cancer staging and has encouraged a therapeutic capability that may parallel the evolution of endoscopic retrograde cholangiopancreatography (ERCP) from a diagnostic to a therapeutic procedure. Injection with therapeutic agents can also be accomplished under EUS guidance leading to many therapeutic techniques being developed for the treatment of pancreatic cancer. Pancreatic cancer is the fourth leading cause of cancer-related deaths in the United States. According to the American Cancer Society, estimated 33,730 Americans will be diagnosed with pancreatic cancer in 2006 [1]. The disease is associated with a high mortality rate and the 5-year survival rate is estimated to be only 4% with the median survival of less than 6 months in untreated patients [1]. Currently, surgical resection is the only opportunity for a cure. However, surgical resection is possible in only 15% of cases due to the late presentation of the disease with a 5-year survival of approximately 20% [2, 3]. When the tumor is unresectable, chemotherapy, radiation therapy, or a combination thereof can be used to increase overall survival and to improve the quality of life [4]. Consequently, pancreatic cancer has become a target for novel therapies such as immunotherapy and gene therapy. This review will focus on the available evidence of EUS as a therapeutic intervention for pancreatic cancer, including EUS-guided fine-needle injection therapy, EUS-guided radiofrequency ablation, EUS-guided photodynamic therapy, and EUS-guided celiac plexus neurolysis.