Evaluation of 68Gallium-DOTATATE PET/CT for Detecting Neuroendocrine Tumors

Background: * Neuroendocrine tumors (NETs) are rare malignancies occurring in the gastrointestinal tract, islets of the pancreas, lung, adrenal medulla and thyroid C-cells. * Their incidence has increased over the last decade, with an incidence of 6 per 100,000 persons a year and they represent 0.46% of all malignancies. * Most NETs are sporadic, but they can be part of familial cancer syndromes such as multiple endocrine neoplasia type 1 (MEN1), MEN2, and neurofibromatosis type 1 (NF1) or Von Hippel-Lindau (VHL) syndrome. * Surgical resection remains the only curative treatment option for patients with NETs but 80% of patients are diagnosed with advanced (metastatic, locally inoperable, or recurrent) disease. * The main prognostic factor in patients with NET is the extent of disease. * The best imaging technique for detecting unknown primary and metastatic NETs has yet to be determined. * NET cells express somatostatin receptors that can be targeted with radiolabeled 68Gallium-DOTATATE (Octreotate) for imaging purposes. * The primary goal of this protocol is to determine the accuracy of a new somatostatin receptor targeted imaging technique, using 68Gallium-DOTATATE PET/CT to detect unknown primary and metastatic NETs. Objectives: -To determine the accuracy of 68Gallium-DOTATATE PET/CT scans in detecting unknown primary and metastatic gastrointestinal and pancreatic neuroendocrine tumors. Eligibility: * Patients with: * suspicion of NET on axial imaging (CT/magnetic resonance imaging (MRI)/fluorodeoxyglucose-positron emission tomography (FDG PET) and/or * biochemical evidence of NET (serum/urinary) based on elevated levels of chromogranin A, pancreatic polypeptide, neuron-specific enolase, vasoactive intestinal polypeptide, serotonin (urinary 5-HIAA), gastrin, somatostatin, catecholamines, metanephrines, calcitonin, fasting insulin, C-peptide (proinsulin), glucagon and/or * familial predisposition to NET in patients with multiple endocrine neoplasia type 1 (MEN1) and VHL. * Age greater than or equal to 18 years of age. * Patients must be willing to return to National Institutes of Health (NIH) for follow-up. Design: * Prospective study. * A 68Ga-DOTATATE PET/CT scan will be done in patients with suspicious lesions, unknown primary tumor or metastatic gastrointestinal or pancreatic neuroendocrine disease found on anatomic imaging (CT/MRI) or in patients having biochemically active disease. * Both functional and non-functional solid tumors will be included in this study. Furthermore, asymptomatic and symptomatic, sporadic and familial cases of NETs (such as Von Hippel-Lindau (VHL), MEN1) will be included. * Demographic, clinical and pathologic data will be collected from the medical record and patient interview for each patient. Data will be stored in a computerized database. * After their initial on-study evaluation, patients will be staged according to findings on imaging studies with respect to primary tumor site, size and metastases. Surgical resection of NET and/or medical managements will be recommended based on standard practice guidelines. In patients who undergo surgical treatment, the samples will be immediately stored until molecular analysis. * Follow up will be done yearly for a total duration of 5 years. This includes a yearly imaging study and a biochemical and clinical evaluation, to assess tumor growth and disease progression. * We estimate that the accrual rate will be 3-10 patients per month; the total accrual period for this study will be 10 months to 3 years.