Cardiac Metastases in Neuroendocrine Neoplasms: A Single-Center Experience of Clinical Characteristics and Outcomes.

Background/Objectives: Cardiac metastases (CM) represent a rare manifestation of neuroendocrine neoplasms (NEN). Detailed clinical characteristics and significance remain understudied. Methods: We retrospectively evaluated 1201 patients with NEN treated at an ENETS Center of Excellence to determine prevalence, clinical features, and outcomes of cardiac metastases. CM were identified in 15 patients (prevalence 1.25%) through multimodal imaging, incorporating somatostatin receptor positron emission tomography/computed tomography (SSTR PET/CT). Metachronous CM occurrence accounted for 93% of cases. Results: The majority of patients showed well-differentiated tumors (G1/G2), with ileum being the most frequent site of origin. Clinical symptoms attributable to CM were observed in 27% of affected patients. Following CM detection, therapeutic management was adjusted in 73% of cases, most frequently by initiating peptide receptor radionuclide therapy (PRRT) n = 8, 53%. Median overall survival (OS) from CM diagnosis was 95 months, with an estimated 5-year survival rate of 77%, with a 5-year OS from NEN diagnosis of 87%. Conclusions: CM in NEN are rare and often clinically silent, with SSTR PET/CT proving essential for detection. While treatment adjustments were frequently observed, particularly with PRRT, OS remained favorable, indicating that the presence of CM in NEN serves as an indicator of metastatic spread rather than a standalone diagnostic determinant of survival. Larger, prospective studies are needed to further validate these findings and to better define the clinical implications of CM in NEN.