Use of somatostatin receptor scintigraphy to image extrahepatic metastasesof neuroendocrine tumors

Background. The presence of lymph node metastases significantly influences the modality of treatment in patients with liver metastases of neuroendocri ne tumors (NET). Somatostatin receptor scintigraphy (Octreo-Scan, Mallinckr odt-Diagnostica, Petten, the Netherlands) is a method for localization and staging NET: The aim of our prospective study was to evaluate the effective ness of somatostatin receptor scintigraphy in the identification of extrahe patic tumor spread. Methods. Thirty-five patients with liver metastases of NET were studied ove r a 5-year period. The presence of NET was confirmed histologically in all cases. To detect extrahepatic metastases or local tumor recurrence, convent ional imaging techniques and somatostatin receptor scintigraphy were carrie d out. Results. In correlation with the findings of conventional imaging methods, somatostatin receptor scintigraphy confirmed liver metastases in all patien ts. Additionally, 19 of 35 patients (54.2 %) had extrahepatic: tumor lesion s not detected by other imaging techniques. Of those, 15 had extensive abdo minal or thoracic lymph node metastases, 3 patients had bone metastases, an d in 1 patient with bronchial carcinoid local tumor recurrence was detected . All 19 patients were excluded from further evaluation for liver resection or transplantation and subjected to conservative treatment. The somatostat in receptor scintigraphy sensitivity, confirmed at the time of operation, w as 91.6%. In I patient, in whom cluster transplantation was performed, soma tostatin receptor scintigraphy failed to disclose disseminated carcinosis o f the pleural cavity, detected at autopsy (false-negative rate 8.3 %). Conclusion. In our experience, somatostatin receptor scintigraphy provides a highly sensitive diagnostic method to localize metastases of NET: We reco mmend somatostatin receptor scintigraphy before liver surgery in every pati ent with hepatic metastases of NET to identify candidates suitable for rese ction.