Emerging applications of endoscopic ultrasound in gastrointestinal cancers.

Endoscopic ultrasound (EUS) has been adopted into numerous interventional techniques and strategies that promise to improve diagnosis and management of gastrointestinal (GI) cancers. EUS-guided fine-needle aspiration (EUS-FNA) is recommended as a procedure of choice for tissue diagnosis of pancreatic cancer. Potential benefits of EUS-FNA in diagnosis of pancreatic cancer include the ability to detect small, discrete lesions compared with conventional imaging and the ability to provide staging information by examination of blood vessels surrounding the pancreas. EUS-FNA currently is being evaluated in strategies for improving diagnosis in pancreatic cancer through analysis of molecular markers, including strategies for distinguishing malignant pancreatic cysts. EUS-guided fineneedle injection currently is being investigated in a broad range of settings in GI cancers, including use in intratumoral injection in pancreas and esophageal cancers, ethanol lavage for nonmalignant pancreatic cystic tumors, and brachytherapy in nonresectable pancreatic cancer. Other applications of EUS currently being evaluated include EUS-guided biliary access in patients with unsuccessful endoscopic retrograde cholangiopancreatography and EUS-guided anastamoses in the GI tract. EUS-guided interventions have enormous potential to advance diagnosis and treatment of GI cancers.