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 (< or =1.5 mg/day) and/or interferon-alpha, underwent ultra-high-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 1 partial remission were observed in patients with functional midgut 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 ultra-high-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.