Background: This study was conducted to evaluate the effects of tumor removal and body weight loss on insulin resistance.
Methods: Insulin sensitivity was examined in 12 patients with cancer and stable weight and five patients with cancer and weight loss before operation, six patients after complete tumor removal, and three normal volunteers (control) by euglycemic hyperinsulinemic glucose clamp.
Results: Glucose metabolized (milligrams per kilogram per minute), metabolic clearance rate of glucose (milliliters per kilogram per minute), and glucose metabolized per unit of insulin (milligrams per kilogram per minute/microunits per milligram) were significantly decreased in the cancer group compared with the control (4.50 +/- 1.32 vs 8.11 +/- 0.56 mg/kg/min, 5.26 +/- 2.22 vs 10.67 +/- 1.98 ml/kg/min, and 4.34 +/- 1.16 vs 8.92 +/- 1.03 mg/kg/min/uU/ml, respectively), regardless of the weight loss. Glucose metabolized, metabolic clearance rate of glucose, and glucose metabolized per unit of insulin ratio were significantly increased after tumor removal (3.87 +/- 0.97 vs 4.80 +/- 1.30 mg/kg/min, 4.03 +/- 1.32 vs 5.67 +/- 2.14 ml/kg/min, and 4.14 +/- 1.19 vs 5.26 +/- 1.32 mg/kg/min/uU/ml, respectively); however, increase in these values did not reach normal control levels.
Conclusions: Our results would suggest that insulin resistance in patients with cancer was not caused by cancer-associated malnutrition but at least in part by tumor itself.