Carcinoid heart disease and urinary 5-HIAA in patients with pancreatic neuroendocrine tumors.

e16350 Background: Neuroendocrine tumors (NETs) can cause carcinoid syndrome and carcinoid heart disease (CHD), leading to pulmonic or tricuspid fibrosis and right heart failure. CHD due to pancreatic NETs (PNETs) is rare and has previously only been described in select case reports. However, a subset of PNET patients have elevated urinary 5-HIAA, suggesting CHD may be underdiagnosed in this population. We aimed to characterize CHD prevalence and identify risk factors in PNET patients. Methods: We collected clinical characteristics of PNET patients from a tertiary care center and compared those with elevated 24-hour urine 5-HIAA (N = 19) to those without (N = 124). Results: The elevated urine 5-HIAA group had a median 5-HIAA level of 14 mg/24 h (range: 8.8–571 mg/24 h). Comparing the elevated and non-elevated 5-HIAA groups (Table 1), no differences were seen in the proportion of female patients (37% vs. 44%, p = 0.6), White race (68% vs. 60%, p = 0.7), Hispanic ethnicity (16% vs 11%, p = 0.4), proportion of stage 4 patients (68% vs. 55%, p = 0.3), and proportion of pathologic grade 2-3 patients (63% vs. 49%, p = 0.3). Patients with elevated urinary 5-HIAA had a higher prevalence of bone metastases (47% vs. 12%, p < 0.001) and were more likely to receive radiation therapy to metastatic sites (16% vs. 1.6%, p = 0.011). Two patients with elevated urinary 5-HIAA developed carcinoid heart disease, leading to new right ventricular dysfunction and tricuspid regurgitation. Neither of these patients had other symptoms of carcinoid syndrome, such as flushing, diarrhea, or shortness of breath. Conclusions: Our findings suggest that elevated urine 5-HIAA levels may be associated with carcinoid heart disease in the absence of typical carcinoid syndrome symptoms. Future work may establish serial urine 5-HIAA measurements as a monitoring strategy in PNET patients. Clinical and demographic characteristics of patients. Characteristic Normal urine 5-HIAA (N= 124) Elevated urine 5-HIAA(N= 19) P value Female 54 (44%) 7 (37%) 0.6 Stage 4 68 (55%) 13 (68%) 0.3 Pathologic grade 2-3 60 (49%) 12 (63%) 0.3 Liver Metastases 65 (52%) 14 (74%) 0.08 Bone Metastases 15 (12%) 9 (47%) <0.001 Maximum urine 5-HIAA (mg/24 h), mean (range) 14 (8.8, 571) Flushing or diarrhea 0 (0%) 2 (11%) <0.001 Carcinoid heart disease 0 (0%) 2 (11%) <0.001 Surgery 39 (31%) 4 (21%) 0.4 Radiation 2 (1.6%) 3 (16%) 0.017