Clinical application of ultrasonic mini-probes in esophageal cancer: The experience of NTUH

Endoscopic ultrasonography (EUS) has been widely applied not only in gastrointestinal tract but also in pancreatobiliary diseases. One of the important fields is esophageal cancer staging. In the past, traditional balloon-type echoprobe has been used to evaluate the stage of esophageal cancer, but with many limitations including inability to pass through stenosis and compression of mucosal lesions by balloon. With improvement of the equipment, thin ultrasonic probe has been applied in EUS examination. To evaluate its role in staging esophageal cancer, 147 cases with 164 sessions undergoing esophageal EUS with thin ultrasonic probe (Olympus, UM2R/3R) were assessed. Among them, 47 cases with 54 sessions were esophageal cancer. Echo beam could penetrate well in all patients except two cases with advanced cancer. In 29 stenotic tumors that panendoscope could not transverse, thin ultrasonic probe still could pass though them with complete scanning in 21(72%) of them. For 12 cases with operation, patients except two pathological correlation showed ultrasonic probe had 100%, 66%, 86% accuracy in T1, T2, T3 staging respectively. For N staging, sensitivity, specificity and accuracy were 83%, 83% and 83% respectively. Neither complications nor breakage of probe occurred during these examinations. These data indicated that thin ultrasonic probe is a new satisfactory method in staging of esophageal cancer.