EUS-Guided Antitumor Therapy for Pancreatic Tumors

Abstract

Endoscopic ultrasound (EUS) is a very useful modality for the diagnosis and staging of pancreatic masses. With the advent of EUS-guided fine-needle aspiration technology, this modality has made a tremendous leap from imaging modality to histologic diagnosis and therapeutic intervention. EUS offers high-resolution images of and unparalleled access to the pancreas. After locating the tip of the echoendoscope in the duodenum or stomach, several drugs or local treatment modalities can be delivered directly into the pancreas. EUS-guided ethanol lavage with/without paclitaxel injection has been tested for the treatment of cystic tumors of the pancreas, with complete resolution of cystic tumor being observed in up to 70-80% of patients. Ethanol injection is also performed for the management of solid neuroendocrine tumors of the pancreas. Various type of EUS-guided injection have also been investigated for the treatment of pancreatic cancer. An activated allogenic mixed lymphocyte culture (Cytoimplant) was injected in patients with advanced pancreatic cancer. A replication-deficient adenovirus vector carrying the tumor necrosis factor-alpha gene was also delivered intratumorally by EUS. ONYX-015 is an oncolytic attenuated adenovirus that exhibits replication preferentially in malignant cells, causing cell death, and this has also been injected into pancreatic cancers under EUS guidance. EUS-guided local ablation therapies such as radiofrequency ablation, photodynamic therapy, and brachytherapy are also under investigation. EUS-guided fine-needle injection for various solid or cystic lesions is a rapidly expanding field. This article reviews the various applications of EUS for the treatment of pancreatic tumors.

Keywords: Brachytherapy; Cystic tumor; Cytoimplant; Endoscopic ultrasonography; Immunotherapy; Pancreas cancer; Photodynamic therapy; Radiofrequency ablation.

Fig. 1

Endoscopic ultrasonography (EUS)-guided pancreatic cystic tumor ablation. (A) For the ablation of pancreatic cystic tumor, a fine, 22-gauge needle was inserted into the cystic cavity. (B) The cystic fluid was aspirated and found to be clear. (C) After cystic fluid aspiration, 99% ethanol was injected into the cavity and left for 5 minutes to cause epithelial ablation. (D) CT scan before EUS-guided treatment. A cystic tumor (3.5×3.1×2.5 cm) was located in the body of the pancreas (arrow). (E) CT scan taken 6 months after EUS-guided treatment, showing that the cystic tumor had disappeared (arrow).