Ultra-high-dose lanreotide treatment in patients with metastatic neuroendocrine gastroenteropancreatic tumors

Background: Symptomatic control and occasionally even tumor regression of functional neuroendocrine tumors (NET) of the gastroenteropancreatic (GEP) system can be achieved by somatostatin analogues. Assuming a dose-dependent antiproliferative effect of somatostatin analogues, we performed a study with the somatostatin analogue lanreotide in ultra-high dosages in patients with progressive, metastatic GEP NET. Patients and Methods: 30 patients with metastatic GEP NET, progressive during treatment with somatostatin analogues (less than or equal to 1.5mg/day) and/or interferon-a, underwent ultrahigh-dose lanreotide therapy (5 mg lanreotide s.c. three times a day). Tumor growth was evaluated every 3 months. Serum chromogranin A, serum serotonin as well as urinary 5-hydroxyindoleacetic acetic acid levels were also determined at 3-month intervals. In patients with functional tumors, tumor-related symptoms were documented. Results: After a 1-year treatment period with ultra-high-dose lanreotide, 1 complete and i partial remission were observed in patients with functional mid-gut NET. Eleven patients had stable disease and 11 patients showed continuing tumor growth after 3-12 months of treatment. Symptoms decreased significantly during therapy. Conclusions: Our data show that ultrahigh-dose lanreotide treatment in patients with metastatic GEP NET can lead to control of both symptoms and proliferation in at least some patients refractory to conventional therapies.