Pancreatic Volume Predicts Postoperative Risk of Exocrine Pancreatic Insufficiency

New research into the relationship between partial pancreatectomy and the subsequent incidence of exocrine pancreatic insufficiency finds a strong positive correlation between the volume of tissue removed and subsequent complications.

Japanese investigators used ¹³C-labeled mixed triglyceride breath tests to assess exocrine pancreatic function in 227 patients after they had undergone either pancreatoduodenectomy (174 patients) or distal pancreatectomy (53 patients). Patients whose % ¹³CO₂ cumulative dose at 7 hours was <5% were deemed to suffer pancreatic insufficiency. The investigators then waited for a median period of 7 months, used abdominal dynamic computed tomography to assess remnant pancreatic volume and looked for clinical or pathological factors that predicted which patients would develop exocrine pancreatic insufficiency.

Remnant pancreatic volume was the only independent factor that was correlated with pancreatic function, but it was strongly correlated (r = .509, p< .001). The cut-off volume that maximized the ability to predict which 128 patients developed pancreatic insufficiency (to the extent that anything measured after a median of 7 months can be said to “predict” anything that was detectable after 7 hours) was 24.1 ml as measured by receiver operating characteristic curve analysis.

Patients with less than 24.1 ml of pancreas left after surgery had nearly 6 times the risk of developing pancreatic insufficiency as patients who retained a greater volume of the organ (hazard ratio, 5.94; 95% confidence interval; 2.96—12.3; p<0.001).

“Remnant pancreatic volume is associated closely with postoperative exocrine pancreatic insufficiency after pancreatectomy,” concluded the investigators, whose findings appeared in Surgery. “Remnant pancreatic volume may predict postoperative PEI in patients who undergo pancreatectomy.”

The new study is not the first to find that a large number of patients who undergo pancreatectomy develop pancreatic insufficiency. To the contrary, a round-up of previous research that was recently published in Nederlandse Vereniging Voor Gastro-Enterologie, found similar data in 9 observational studies of cancer patients who underwent some form of the surgery.

The studies included in that paper included data on 664 patients. Of those, 333 (50%) underwent pancreatoduodenectomy, 23 (3%) total pancreatectomy, 114 (17%) distal pancreatectomy and 194 (33%) no resection due to locally advanced pancreatic cancer. Unlike the patients in the new study, many of the patients in these older studies had pancreatic insufficiency before they underwent surgery.

“Median preoperative prevalence of exocrine pancreatic insufficiency was 44% (range 42-67%) before pancreatoduodenectomy; 20% (16-67%) before distal pancreatectomy; 63% before total pancreatectomy; and 50% in unresectable patients. The median prevalence of exocrine pancreatic insufficiency at least 6 months postoperative was 84% (36-100%) after pancreatoduodenectomy. Mean prevalence after distal pancreatectomy was 74% (67-80%); and 100% after total pancreatectomy,” the authors of that study wrote. “In conclusion, exocrine pancreatic insufficiency is frequently seen in patients before resection for pancreatic or peri-ampullary cancer. The prevalence increases markedly following resection.”

Still, the authors of the new study from Japan note, previous research had never established any firm correlation between remnant pancreatic volume and postoperative pancreatic function, let alone calculated a threshold volume that predicted an elevated risk for the condition. “Our aim,” they wrote, “was to clarify a relationship between remnant pancreatic volume and postoperative exocrine pancreatic insufficiency.”