Pancreatic exocrine insufficiency (PI) secondary to chronic use of long-acting (LA) somatostatin analogues (SA) in patients (pts) with gastroenteropancreatic neuroendocrine tumors (GEP-NETs).

Abstract

454 Background: SA are used in GEP-NETs and acromegaly. Side effects of SAs include biliary disorders, gastrointestinal disorders, injection-site pain and hyperglycemia. PI is often misdiagnosed as disease progression or failure to SA or diagnosed after a delay in pts receiving SA. We present our experience with PI developing in pts following chronic use of SA. Methods: Retrospective chart and pharmacy review of GEP-NETs pts (6/2009 - 6/2017) was completed. Data including demographics, dose/duration of long and short-acting SA, antidiarrheal, pancreatic enzyme replacement (PER), proton pump inhibitors (PPI), chromogranin A (CgA), urine 5-HIAA and quantitative fecal fat test (QFFT) was collected. Results: 110 GEP-NETs pts (Med. age: 56 yr) were identified. 104 pts received LA Octreotide acetate and 6 Somatuline Depot Injection. Of these, 23 received SA octreotide for worsening diarrhea, 96 had intensification of antidiarrheal and 1 got telotristat ethyl. 79 pts were evaluated by nutritionist and/or gastroenterology. QFFT was performed in 47 pts with worsening diarrhea despite stable or improved CgA/urine 5-HIAA. 19 had evidence of steattorrhea and received PER at a dose of 72,000 lipase units per meal. 13 received PPI concomitantly while 6 started when symptoms did not improve with PER. In addition, low fat diet was recommended. 14 of 19 had improvement in diarrhea within 4-8 weeks. 2 pts were non-compliant and 3 were found to have motility disorders. Deficiency of vitamins and trace elements was found in 11 of 19 pts, who received supplementation. Conclusions: Our experience constitutes first study addressing PI as a rare but serious complication of chronic use of SA. Although SA are used to treat diarrhea, paradoxically they can worsen diarrhea secondary to PI. It is believed that SA may inhibit secretion and release of hormones (amylase, trypsin, lipase, secretin, CCK, motilin, bile acid) leading to PI. Early recognition and diagnosis of this under-diagnosed and under-reported side effect of SA can improve not only diarrhea and weight in these pts but also can reduce cost of using short-acting SA and antidiarrheal.