Objective: The aim of the study was to characterize the metabolic changes in non-weight-losing patients with cancer of the bladder and to investigate the effect of tumor stage. The kinetics of glucose, glycerol, and urea metabolism were assessed in 22 weight-stable patients with non-metastatic bladder cancer (tumor stage p </= T2, n = 8; tumor stage p > T2, n = 14) and 10 patients with benign uterine myoma (controls).
Methods: The kinetics of glucose, glycerol, and urea metabolism were assessed by [6,6-(2)H(2)]glucose, [1,1,2,3,3-(2)H(5)]glycerol, and [(15)N(2)]urea. Plasma concentrations of glucose, glycerol, urea, lactate, free fatty acids, insulin, glucagon, cortisol, epinephrine, and norepinephrine also were determined.
Results: Plasma concentrations of glucose, urea, and insulin were higher in cancer patients than in controls (P < 0.05). Whereas glucose production was similar in both groups, glucose clearance was lower in patients with bladder cancer (P < 0.05). Glycerol turnover rate was comparable between groups. Whole-body urea synthesis rate was higher in the cancer group than in the control group (P < 0.05), but there was no difference in urea synthesis when calculated per kilogram of fat-free body mass. Plasma concentrations of glycerol, lactate, free fatty acids, glucagon, cortisol, epinephrine, and norepinephrine were similar in both groups. There was no difference in any parameter between patients with an early tumor stage (p < T2) and patients with a later tumor stage (p > T2).
Conclusion: Patients with bladder cancer had a lower rate of glucose clearance than did control subjects. Lipid metabolism was not affected, whereas urea synthesis rate was elevated in cancer patients. However, when expressed per kilogram of fat-free body mass, no difference in protein breakdown could be observed. The tumor stage had no effect on glucose, lipid, or protein metabolism.