Serum angiogenic factors in patients with neuroendocrine tumors of abdominal organs.

The initial (before treatment) levels of VEGF, endostatin, and tumor necrosis factor-beta (TNF-beta) were measured in the sera of 20 patients with malignant and benign neuroendocrine tumors of the abdominal organs and 25 healthy controls. The initial levels of VEGF, endostatin, and TNF-beta in the total group of patients with neuroendocrine tumors of abdominal organs did not differ from the control. A significant difference was detected between the mean serum concentrations of endostatin in patients with benign and malignant neuroendocrine tumors: 64.1+/-14.7 and 107.8+/-14.1 ng/ml, respectively (p=0.043). The content of VEGF, endostatin, and TNF-beta did not correlate with patients' gender and age. A direct correlation between endostatin, TNF-beta concentrations and maximum size of the primary tumor was detected in patients with malignant neuroendocrine tumors. Direct correlations between the initial levels of VEGF and endostatin and an inverse correlation between VEGF and TNF-beta concentrations were detected in patients with benign neuroendocrine tumors. Relapse-free survival was significantly lower in patients with serum endostatin concentration >100 ng/ml and TNF-beta<30 pg/ml.

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).