The Impact of Pancreaticoduodenectomy on Endocrine and Exocrine Pancreatic Function: A Prospective Cohort Study Based on Pre- and Postoperative Function Tests

Background/objectives: Studies reporting on function after pancreatic surgery are frequently based on diabetes history, fasting glycemia or random glycemia. The aim of this study was to investigate prospectively the evolution of pancreatic function in patients undergoing pancreaticoduodenectomy based on proper pre- and postoperative function tests. It was hypothesised that pancreatic function deteriorates after pancreaticoduodenectomy.

Methods: Between 2013 and 2016, 78 patients undergoing pancreaticoduodenectomy for oncologic indications had a prospective evaluation of their endocrine and exocrine pancreatic function. Endocrine function was evaluated with the 75 g oral glucose tolerance test (OGTT) and the 1 mg intravenous glucagon test. Exocrine function was evaluated with a 13C-labelled mixed-triglyceride breath test. Tests were performed pre- and postoperatively.

Results: In 90.5% (19/21) of patients with preoperatively known diabetes, no change in endocrine function was observed. In contrast, endocrine function improved in 68.1% (15/22) of patients with newly diagnosed diabetes. 40% (14/35) of patients with a preoperative normal OGTT or prediabetes experienced deterioration in function. In multivariate analysis, improvement of newly diagnosed diabetes was correlated with preoperative bilirubin levels (p = 0.045), while progression towards diabetes was correlated with preoperative C-peptidogenic index T (p = 0.037). A total of 20.5% (16/78) of patients had pancreatic exocrine insufficiency preoperatively. Another 51.3% (40/78) of patients deteriorated on exocrine level. In total, 64.1% (50/78) of patients required pancreatic enzyme-replacement therapy postoperatively.

Conclusions: Although deterioration of endocrine function was expected after pancreatic resection, improvement is frequently observed in patients with newly diagnosed diabetes. Exocrine function deteriorates after pancreaticoduodenectomy.