Background: Few data exist regarding outcomes after resection versus embolic treatment of symptomatic metastatic carcinoid and neuroendocrine tumors. The purpose of this study was to determine whether cytoreduction provides any benefit over embolic management of diffuse neuroendocrine tumors., Methods: A prospective database of 734 patients treated at our institution was retrospectively queried for symptomatic metastatic tumors treated with embolization or cytoreduction. Patients were compared with regard to pretreatment performance status, relief of symptoms, and survival., Results: A total of 120 patients were identified: 59 undergoing embolization and 61 undergoing cytoreduction. Twenty-three patients had palliative cytoreduction (gross residual disease). Pretreatment performance status (Eastern Cooperative Oncology Group) was similar for both groups: .7+/-.70 (embolization) versus .8+/-.72 (cytoreduction; P=.27). Complete symptomatic relief was observed in 59% and partial relief in 32% of patients who underwent embolization, with a mean symptom-free interval of 22+/-13.6 months. A total of 69% of patients who underwent cytoreduction had complete symptomatic relief, and 23% had partial relief (P=.08 vs. embolization). The mean duration of relief was 35+/-22.0 months (P<.001 vs. embolization). The mean survival for the patients who underwent embolization was 24+/-15.8 months versus 43+/-26.1 months for those who underwent cytoreduction (P<.001). Survival in patients who underwent palliative cytoreduction was 32+/-18.9 months (P<.001 vs. embolization), whereas it was 50+/-27.6 months in patients who underwent curative resection (P<.001 vs. embolization; P<.001 vs. palliative)., Conclusions: Cytoreduction for metastatic neuroendocrine tumors resulted in improved symptomatic relief and survival when compared with embolic therapy in this nonrandomized study. Cytoreduction should be pursued whenever possible even if complete resection may not be achievable.