P037 - CLINICAL CHARACTERISTICS, ECHOCARDIOGRAPHIC FEATURES, AND OUTCOMES OF PATIENTS WITH NEUROENDOCRINE TUMOURS AND CARCINOID HEART DISEASE IN A CONTEMPORARY CANADIAN COHORT

Background: Neuroendocrine tumours (NETs) are uncommon cancers that can secrete vasoactive hormones. Approximately 50% of metastatic small bowel NETs develop carcinoid syndrome, with up to 50% historically developing carcinoid heart disease (CHD). With advances in medical therapy, contemporary characteristics and prognosis of CHD are unclear. We sought to evaluate clinical characteristics, echocardiographic features, and outcomes of patients with NETs and CHD in a contemporary Canadian cohort.

METHODS AND RESULTS: This retrospective cohort study analyzed patients undergoing echocardiograms at a tertiary cancer centre-affiliated laboratory between 2013-2023 with references to NETs or CHD in reports. Patients were classified based on whether CHD developed during the study period. Baseline clinical characteristics, treatments, and outcomes were compared between the two groups. Baseline echocardiographic data (≤6 months from NET diagnosis) were reviewed to characterize features associated with CHD development. Interventions were compared between patients who survived < 2.5 years after CHD diagnosis and those who survived ≥2.5 years or were alive by the end of the study period. In this 10-year period, 87 patients with NETs were identified [42 (48%) female; median age 61 (IQR 53-69) years] and 18 (21%) developed CHD [8 (44%) female; median age 66 (IQR 59-71) years]. Primary NETs of small bowel origin were more common in patients with CHD than those without CHD (83% vs. 55%, p=0.032). CHD patients exclusively had right-sided valve involvement: 100% tricuspid and 61% pulmonary; 3 (16%) had a patent foramen ovale. Compared to non-CHD patients at baseline echo, CHD patients demonstrated higher mean right atrial volume index (41mL/m2 vs 24mL/m2, p=0.001), higher mean right ventricular (RV) basal diameter (40mm vs. 34mm, p=0.006), and more frequent RV dysfunction (22% vs. 0%, p< 0.001). Surgical valve replacement was performed in 9 (50%) CHD patients and was indicated but deferred in 6 (33%) due to competing comorbidities. The median survival of CHD patients from NET diagnosis was 6.6 vs. 13.4 years without CHD (p < 0.01). NET progression and refractory heart failure were main reasons for mortality. Among CHD patients, primary NET resection was significantly associated with improved survival (p=0.006). Tyrosine kinase inhibitors and radiation therapy showed trends toward improved survival.

Conclusion: In our cohort of patients with NETs, CHD prevalence was lower than previously reported with cases affecting only right-sided valves. Contemporary therapeutics, including medical and radiation therapies, showed trends toward improved survival. Further studies are needed to determine reasons behind differences in CHD prevalence, valvular involvement, and outcomes in the current era.