Clinical and biochemical aspects of the carcinoid syndrome in neuroendocrine tumors of the abdominal and retroperitoneal organs and its impact for the disease prognosis.

Overall and relapse-free survival of 238 patients with neuroendocrine tumors of the abdominal and retroperitoneal organs was evaluated with consideration for the presence of the carcinoid syndrome. The incidence of the carcinoid syndrome was 15.6%. The presence of the carcinoid syndrome was inessential for survival and relapse prognosis in patients with neuroendocrine tumors of the abdominal and retroperitoneal organs. A trend to the development of earlier relapses was noted in patients with this syndrome. Diarrhea was found to be a prognostically unfavorable factor. The time of the carcinoid syndrome development was prognostically significant in patients with malignant neuroendocrine tumors. The mean secretion of epinephrine, norepinephrine, and dopamine with daily urine was significantly higher in patients with the carcinoid syndrome. A significant positive correlation between urinary excretion of catecholamines was detected (r=0.53; p<0.05).