Efficacy and Safety of Prolonged-Release Lanreotide in Patients With Gastrointestinal Neuroendocrine Tumors and Hormone-Related Symptoms

PURPOSE: To evaluate the prolonged release (PR) of the long-acting somatostatin analog lanreotide in patients with gastrointestinal neuroendocrine tumors and its effect on hormone-related symptomatology, tumor markers, tumor size, tolerability, and quality of life (QOL). PATIENTS AND METHODS: Eligible patients had the following substantial daily symptoms: for patients with carcinoid tumors, three or more stools and/or 1.5 or more flushing episodes; for patients with gastrinoma, greater than 50% elevated basic acid output; and for patients with vasoactive intestinal peptide-secreting tumors (VIPomas), four or more stools and/or a stool volume of ≥ 800 mL, a measurable tumor, and an elevated biochemical tumor marker (≥ two times the upper limit of the normal reference range). Lanreotide PR was administered intramuscularly every 14 days at 30 mg for 6 months. We measured efficacy by studying symptoms, tumor markers, tumor size, and QOL. Side effects were scored according to the National Cancer Institute's toxicity grading system and ultrasound examination of the gallbladder. RESULTS: Fifty-five patients were included in the study (48 patients with carcinoid tumors, six patients with gastrinoma, and one patient with VIPoma). Symptomatic improvement (> 50% reduction) occurred in 38% of the assessable patients with carcinoid tumors, in 67% of the gastrinoma patients, and in the VIPoma patient. Tumor markers normalized in two of 45 assessable patients, 19 patients exhibited a reduction (> 50%), 19 patients exhibited no change, and tumor markers rose by more than 50% in five patients. Tumor size was reduced in two of 31 assessable patients and remained stable in 25 patients; four patients experienced progression. QOL assessments after 1 month showed improvements in emotional and cognitive function, and diminished fatigue, sleeping disorders, and diarrhea. Eight of 30 assessable patients developed gallstones. CONCLUSION: Lanreotide PR is a well-tolerated somatostatin analog with significant clinical, biochemical, and antitumor effects that bring about a significant improvement in QOL for patients with neuroendocrine tumors.