Prospective study of the utility of somatostatin-receptor scintigraphy in the evaluation of patients with multiple endocrine neoplasia type 1

Background. Neuroendocrine tumors (NETs) are a potentially lethal component of multiple endocrine neoplasia type 1 (MEN 1). Somatostatin receptor scintigraphy (SRS) can be used to localize NETs and evaluate patients for extraduodenopancreatic disease; its utility in managing MEN 1 is undefined. Methods. All patients with MEN 1 evaluated by SRS from April 1994 to November 1997 are reported. SRS findings were correlated with other imaging studies and operative findings. Results. Thirty-seven SRS studies were performed in 29 patients with MEN 1. SRS identified occult tumor in 36% (4/11) of patients with only biochemical evidence of NET; 2 patients went on to resection. SRS showed tumor in 79% (15/19) of patients with computed tomography (CT)-demonstrated tumor; 30% (6/20) of the SRS lesions were occult on CT. Conversely, 55% (16/29) of CT-identified lesions were occult on SRS. SRS found distant disease in 21% (6/29) of patients. In patients who had previous operations, SRS found tumor in 40% (4/10) of patients, again with both new positive and false-negative results compared with other imaging. SRS also had 3 important false-positive results, including 1 patient who had laparotomy with no tumor identified. Conclusions. SRS is useful in identifying otherwise occult NETs in patients with MEN 1 and can substantially alter management. However SRS also has significant false- positive and false-negative results that demand correlation with other studies.