Preoperative and postoperative levels of plasma protein and amino acid in esophageal and lung cancer patients.

The metabolic changes following thoracic surgery in three groups of patients (esophageal cancer, lung cancer, and hiatus hernia) have been studied. Before operation patients with esophageal cancer, but not those with lung cancer, had significantly lower plasma total protein and albumin than patients with hiatus hernia. After surgery plasma albumin and total protein fell in both esophageal cancer and hiatus hernia patients, a development attributed to poor nutrition and restricted calorie diet in these two groups of patients respectively. With the exception of alanine and arginine in lung cancer patients, and free tryptophan in lung and esophageal cancer patients, the preoperative concentrations of all plasma amino acids were similar in both groups of cancer patients and in those with hiatus hernia. After operation the concentrations of glutamine, total tryptophan, alanine, glycine, and arginine fell sharply, whereas those of phenylalanine, lysine, valine, and leucine were slightly or not at all affected by surgery. The immediate postoperative fall of plasma free amino acids is thought to be due to the increased rate of gluconeogenesis. The rise of free fraction of plasma tryptophan after surgery is related to the raised level of plasma free fatty acids and increased secretions of catecholamines, which is believed to follow surgery.