Effects of Sandostatin LAR on gastrointestinal motility in patients with neuroendocrine tumors

Abstract

Background. Diarrhea is part of the carcinoid syndrome and a significant clinical problem in neuroendocrine tumor (NET) patients. Somatostatin analog (SA) treatment usually alleviates carcinoid diarrhea, but little is known about the objective effects of SA on gastrointestinal transport. Aim. To compare gastrointestinal motility in healthy subjects and NET patients before and during SA treatment. Methods. Twelve NET patients were studied before and during 4 weeks of SA treatment and were compared with 12 healthy controls. Radio-opaque markers were used for the assessment of total gastrointestinal transit time (GITT). Gastric and small intestinal (SI) transit patterns were described via the external tracking of a small magnetic pill ingested by the subjects. Results. Compared with controls, NET patients had a significantly shorter GITT (0.7 days (0.5–1.5) vs. 1.9 days (1.0–2.3)), a shorter SI transit time (184 min (74–307) vs. 322 min (131–376)), and a faster SI velocity (2.16 cm/min (0.91–3.66) vs. 1.29 cm/min (0.76–2.60)) (all p < 0.05) but a similar gastric emptying time. SA treatment was followed by a reduction in bowel movements (five per day (3–12) vs. four per day (1–7; p < 0.02)) as well as an increase in GITT (1.4 days (0.5–2.2; p < 0.05)). Further, a trend was observed toward increased SI transit time (253 min (145–344; p = 0.08)). Gastric emptying time increased during SA treatment (19 min (4–200) vs. 179 min (5–389; p < 0.02)). Elevated chromogranin A (CgA), serotonin, and urinary 5-hydroxyindoleacetic acid (U-5HIAA) levels decreased during SA treatment. Conclusion. NET patients have faster than normal total GITT and SI transit times. SA treatment prolongs gastric emptying and GITT, thereby reducing the number of bowel movements.