Use of ⁹⁰Y SIR-Spheres in the Treatment of Unresectable Hepatic Metastases from Neuroendocrine Tumors

Abstract

Neuroendocrine tumors (NET), and their majority subset carcinoid tumors, are derived from peptide and amine producing or enterochromaf fin cells which originate diffusely within the body. They produce an array of bioactive amines and peptides including neuron-specific enolases, 5-hydroxytryptamine, 5-hydroxytryptophan, synaptophysin, chromogranins A and C, ACTH, growth hormone, serotonin, and a number of others [1]. NET cannot be classified on histologie examination as malignant or benign; that distinction can only be achieved by the identification of metastatic lesions. These tumors will metastasize commonly to either the liver or the bone depending on their cells of origin. The carcinoid syn- drome is another hallmark of malignancy since liver metastases are required to produce the characteristic cutaneous flushing, episodic hypertension, diarrhea, and asthma. Damage to the tricuspid and pulmonic cardiac valves arises from long-standing carcinoid syndrome. Foregut carcinoids, commonly originat- ing in the bronchus, metastasize to bone but the ap- pearance of the carcinoid syndrome is uncommon.