PREOPERATIVE LOCALIZATION OF GASTROINTESTINAL ENDOCRINE TUMORS USING SOMATOSTATIN-RECEPTOR SCINTIGRAPHY

Objective The purpose of this study was to determine the value of soma tostatin-receptor scintigraphy (SRS) in the preoperative localization of gastrointestinal endocrine tumors. The authors report their prelimi nary experiences with this new technique as compared to conventional i maging studies like computed tomography (CT) and ultrasonography (US). Summary Background Data Most endocrine tumors possess high-affinity s omatostatin-receptors. Using the stable, Indium-111 labelled somatosta tin analogue pentatreotid, which binds to these receptors, it is possi ble to detect somatostatin-receptor-positive tumors scintigraphically. Methods In nine patients with various gastrointestinal endocrine tumo rs, SRS, CT, and US were performed before surgical exploration. The pr eoperative imaging studies and intraoperative ultrasound (IOUS) were t hen compared to findings on surgical exploration. Results Twelve prima ry tumors were found in 8 patients at surgical exploration. These prim ary tumors were correctly identified with SRS in five patients, with U S in four patients, and with CT in three patients. In one patient with the Zollinger-Ellison syndrome, scintigraphy suggested a tumor in the area of the hepatoduodenal ligament, while CT and US had negative res ults. The underlying gastrinoma could not be identified despite extens ive surgical exploration. Scintigraphy, CT, and US showed comparable r esults in the detection of metastases in four patients. Conclusions Th e data from this small series suggest that SRS is helpful in the preop erative localization of gastrointestinal endocrine tumors.