Changes in gut hormones, glycaemic response and symptoms after oesophagectomy

BACKGROUND: Oesophagectomy is associated with reduced appetite, weight loss and postprandial hypoglycaemia, the pathophysiological basis of which remains largely unexplored. This study aimed to investigate changes in enteroendocrine function after oesophagectomy. METHODS: In this prospective study, 12 consecutive patients undergoing oesophagectomy were studied before and 10 days, 6, 12 and 52 weeks after surgery. Serial plasma total fasting ghrelin, and glucagon-like peptide 1 (GLP-1), insulin and glucose release following a standard 400-kcal mixed-meal stimulus were determined. CT body composition and anthropometry were assessed, and symptom scores calculated using European Organisation for Research and Treatment of Cancer (EORTC) questionnaires. RESULTS: At 1 year, two of the 12 patients exhibited postprandial hypoglycaemia, with reductions in bodyweight (mean(s.e.m.) 17·1(3·2) per cent, P < 0·001), fat mass (21.5(2.5) kg versus 25.5(2.4) kg before surgery; P = 0·014), lean body mass (51.5(2.2) versus 54.0(1.8) kg respectively; P = 0·003) and insulin resistance (HOMA-IR: 0.84(0.17) versus 1.16(0.20); P = 0·022). Mean(s.e.m.) fasting ghrelin levels decreased from postoperative day 10, but had recovered by 1 year (preoperative: 621·5(71·7) pg/ml; 10 days: 415·1(59·80) pg/ml; 6 weeks: 309·0(42·0) pg/ml; 12 weeks: 415·8(52·1) pg/ml; 52 weeks: 547·4(83·2) pg/ml; P < 0·001) and did not predict weight loss (P = 0·198). Postprandial insulin increased progressively at 10 days, 6, 12 and 52 weeks (mean(s.e.m.) insulin AUC0-30 min : fold change 1·7(0·4), 2·0(0·4), 3·5(0·7) and 4·0(0·8) respectively; P = 0·001). Postprandial GLP-1 concentration increased from day 10 after surgery (P < 0·001), with a 3·3(1·8)-fold increase at 1 year (P < 0·001). Peak GLP-1 level was inversely associated with the postprandial glucose nadir (P = 0·041) and symptomatic neuroglycopenia (Sigstad score, P = 0·017, R2  = 0·45). GLP-1 AUC predicted loss of weight (P = 0·008, R2  = 0·52) and fat mass (P = 0·010, R2  = 0·64) at 1 year. CONCLUSION: Altered enteroendocrine physiology is associated with early satiety, weight loss and postprandial hypoglycaemia after oesophagectomy.