Progression of intracardiac metastases from gastroenteropancreatic neuroendocrine tumors.

Intracardiac metastases from gastroenteropancreatic neuroendocrine tumors (NETs) are rare and challenging to diagnose. Lutetium (Lu)-177 DOTATATE therapy has demonstrated significant benefit in patients with metastatic NET; however, there are limited data regarding the direct impact on cardiac metastases. Patients with intracardiac metastasis from NET were evaluated. Patients were stratified by treatment with Lu-177 DOTATATE. Quantitative assessments of the progression of cardiac metastatic size (maximal diameter) and metabolic activity, as measured by maximal standardized uptake value (SUV max ), were performed on serial 68 Ga-DOTATATE PET imaging. In a cohort of 23 patients, 11 patients (47.8%) received Lu-177 DOTATATE therapy. Through a median of 2.2 years of follow-up, these patients showed some reduction in metastatic burden with a median reduction in maximal diameter of 1.0 mm (IQR: 0.0-3.0) and a median change in SUV max of -1.6 (IQR: -4.4 to 1.5). In contrast, patients who did not receive Lu-177 DOTATATE had some increase in maximal diameter of 0.5 mm (-2.0 to 2.0) and an increase in SUV max of 1.4 (-6.2 to 2.3). Overall, Lu-177 DOTATATE therapy may result in modest regression of intracardiac metastases as assessed by molecular imaging, whereas patients with cardiac metastases who did not receive therapy appeared to show progression.