Detection of bone metastases in patients with endocrine gastroenteropancreatic tumors: Bone scintigraphy compared with somatostatin receptor scintigraphy

Scintigraphy with somatostatin analogs is a sensitive method for the stagin g and therapeutic management of patients with endocrine gastroenteropancrea tic (GEP) tumors. The aim of this study was to compare prospectively somato statin receptor scintigraphy (SRS) using In-111-pentetreotide with bone sci ntigraphy using Tc-99m-hydroxymethylene diphosphonate for the detection of bone metastases. Methods: One-hundred-forty-five patients with proven endoc rine GEP tumors were investigated. Patients were classified according to th e presence of bone metastases as indicated by CT, MRI or histologic data. G roup I included 19 patients with confirmed bone metastases, and group II in cluded 126 patients without bone metastases. Results: In group I, SRS was p ositive in all 19 patients with bone metastases, and bone scintigraphy was positive in 17 patients. Bone metastases were found to occur predominantly in patients with liver metastases. In group II, 5 patients had recent bone surgery for fracture or arthritis. SRS showed bone uptake in 4 of these pat ients, and bone scanning showed abnormal uptake in 5. In 7 of the remaining 121 group II patients, SRS was negative and bone scanning showed abnormal bone uptake suggesting bone metastases. The detection of bone metastases wa s of major prognostic value, because 42% of group 1 patients died during a 2-y follow-up. Conclusion: In patients with GEP tumors, the accuracy of SRS appears to be similar to that of bone scintigraphy for the detection of bo ne metastases.