Glucose metabolism in patients with gastrointestinal malignancy but without excessive weight loss.

Patients with gastrointestinal malignancy demonstrate impaired glucose disposal during steady state hyperglycaemia, 20.5 +/- 1.4 mumol/kg min when compared with controls 28.2 +/- 2.2 mumol/kg min. This appears to be unrelated to antecedent weight loss, but is related to the presence of metastatic spread (P less than 0.05). Insulin response to hyperglycaemia is normal, but analysis of glucose disposal with time suggests insulin resistance as a factor in the causation of impaired glucose disposal. Free fatty acid levels fail to suppress in cancer patients but their role in the causation of insulin resistance remains unclear.