Treatment with 90Y- and 177Lu-DOTATOC in patients with metastatic neuroendocrine tumors

Background. Treatment with Y-90- or Lu-177-DOTATOC has recently been introduced in the palliative treatment Of somatostatin receptor-expressing neuroendocrine tumors (NETs). The aim of the study vias to present clinical experience with Y-90- and Lu-177-DOTATOC therapy in the management of NET. Methods. To prove suitability for treatment each patient underwent scanning with In-111-DTPAOC or Ga-68-DOTATOC positron emission tomography/computed tomography. All patients received [Y-90-DOTATOC] as initial treatment. In case of disease relapse the treatment was repeated. To avoid side effects of repeated [Y-90] applications, a switch to [Lu-177-DOTATOC] was carried out. Clinical, biochemical, and radioimaging responses were documented. Results. Twenty patients with metastatic nonresectable NETs (15 pancreas NETs, 2 midgut AETs, 1 gastrinoma, I paraganglioma, I NET of unknown primary origin) were included. In 8 patients the treatment was repeated more than once (mean, 3 times; range, 2-5 times). After [Y-90] treatment moderate toxicity was observed in 8 patients. No serious adverse events were documentable. After restaging, a partial remission was found in 5 patients, stable disease in 11 patients, and tumor progression in 4 patients. Conclusions. Peplide receptor-targeted radionuclide therapy is a promising, safe, and feasible approach in the palliative therapy of patients with NET.