PURPOSE: To compare the sensitivity of whole body magnetic resonance imaging (WB-MRI) and somatostatin receptor scintigraphy (SRS) for the diagnosis of bone metastases (BM) in patients with well-differentiated gastro-entero-pancreatic endocrine cancer (WD-GEP-EC) and to determine predictive factors of BM.

PATIENTS-METHODS: WB-MRI and SRS were prospectively performed in 79 patients with bronchial (11), thymic (5), gastric (2), duodeno-pancreatic (24), ileal (26), colic (1), or unknown primary (10) WD-GEP-EC.

RESULTS: 36 patients (46%) had 333 BM involving 119 skeletal segments. WB-MRI and SRS were equally sensitive for detecting patients with BM (86% vs. 81%, P=0.56) with 33% of the patients diagnosed with only one procedure. WB-MRI detected more BM than SRS (80% vs. 57%, P=0.017). Compared to SRS, WB-MRI detected more spine BM (96% vs. 45%, P<0.001) and tended to detect more pelvic and lower limb BM (P=0.054 and P=0.06, respectively). Compared to WB-MRI, SRS detected more skull BM (100% vs. 0%, P<0.001) and tended to detect more rib BM (P=0.08). Sternal and upper limb BM were equally detected with WB-MRI and SRS (P=0.32 and P=0.46, respectively)

Bone staging with SRS and spine MRI rather than WB-MRI would have detected 92% of the patients with BM and 83% of all BM. The extent of liver involvement and bronchial-thymic primary tumors were independent predictive factors for BM.

CONCLUSION: We recommend bone staging with SRS and spine MRI in all patients with bronchial-thymic or unknown primary WD-GEP-EC. In case of duodeno-pancreatic or ileal primary, bone imaging may be restricted to patients with liver metastases.