Therapy of the Malignant Carcinoid Syndrome

Abstract
This report discusses the therapy of the malignant carcinoid syndrome in the light of information available in the literature and of the author''s experience with the case of 16 patients studied over the past several years. Therapy of the malignant carcinoid syndrome includes four major approaches: 1) early identification and resection of the primary tumor; 2) inhibition of the peripheral effects of serotonin production; 3) decrease in the production of serotonin by the tumor; 4) direct attack on the metastatic tumor either by surgical removal of isolated metastases, x-irradiation, or the use of chemotherapeutic agents. It is noted that the effectiveness of therapy can be objectively evaluated by changes in carcinoid symptoms, measurements of liver size, and, in addition, it is possible to measure several blood and urinary metabolites of tryptophan which might reflect ultimate anti-tumor activity. It is concluded that a comprehensive program of therapy for the malignant carcinoid syndrome requires aggressive primary and judicious repeat surgical intervention, the use of serotonin antagonists, which are especially effective for the relief of the carcinoid symptoms, and consideration and trial of antitumor chemotherapy with appropriate biochemical and clinical studies carried out in parallel. With few exceptions the various measures for inhibiting serotonin production by the tumor make the patient sicker.