Peptide Receptor Radioligand Therapy Is an Effective Treatment for the Long-Term Stabilization of Malignant Gastrinomas

BACKGROUND: Gastrinomas, a rare group of neuroendocrine tumors, are responsible for severe peptic disease and diarrhea. Although symptomatic control may be achieved with proton-pump inhibitors (PPIs) and somatostatin analogues (SSAs), data are limited regarding the possible antitumor effect of the peptide receptor radioligand therapy (PRRT) with radiolabeled SSAs in gastrinoma patients. The goal of this study was to assess the effect of PRRT on symptoms, gastrin secretion, and tumor load in patients with progressive malignant gastrinomas. METHODS: We retrospectively studied 11 patients with metastatic gastrinomas followed for a mean period of 6 years. All patients were symptomatically treated with PPIs, and 9 of 11 patients received monthly injections of SSAs; all patients had an Eastern Cooperative Oncology Group score of 0-1, and received PRRT ((90)Yttrium- or (177)Lutetium-DOTATOC) for progressive disease. Serum gastrin measurements and radiological assessment (using the Response Evaluation Criteria in Solid Tumors criteria) were performed before and every 3-6 months following PRRT. RESULTS: PRRT induced symptomatic improvement in all patients. The mean serum gastrin decreased significantly from 4831 mI/L to 932.6 mI/L (normal, 40-108 mI/L; P < .001). Periodic radiological surveillance showed complete response in 1 (9%) patient, partial tumor response in 5/11 (45%) patients, and tumor stabilization in 5/11 (45%) patients. In 7/11 (64%) patients, the antitumor effect of PRRT persisted after a median period of 14 months. Four of 11 (36%) patients died due to tumor progression (median time to progression, 11 months); in this group, the mean survival time after the last PRRT was 14 +/- 6.9 months. CONCLUSIONS: PRRT seems to be a promising tool for the management of patients with inoperable or progressive metastatic gastrinomas. Cancer 2011; 117: 1377-85. (C) 2010 American Cancer Society.