Serum endocannabinoids in assessing pain in patients with chronic pancreatitis and in those with pancreatic ductal adenocarcinoma

Background: The endocannabinoid system plays a substantial role in analgesia. Aim: To analyze N-arachidonoylethanolamine (AEA), N-oleoylethanolamine (OEA), linoleoyl ethanolamide (LEA), a-linoleoyl ethanolamine (a-LNEA), N-palmitoylethanolamine (PEA) and N-stearoyl ethanolamine (SEA) in two groups of patients having chronic pancreatic diseases. Patients and methods: Twenty-six patients with chronic pancreatitis, 26 patients with pancreatic ductal adenocarcinoma and 36 healthy subjects were studied. The visual analogic scale (VAS) was used for assessing pain immediately before the venipuncture to obtain blood in all subjects. Six endocannabinoids were measured in serum of the patients enrolled. Results: Only OEA, LEA and PEA serum levels were significantly higher in patients with pain as compared to those without. Using the cutoff values, the sensitivity and specificity of the various endocannabinoids in evaluating pain in patients with chronic pancreatitis and in those with pancreatic ductal adenocarcinoma were: 44.2% and 95.6% for AEA, 83.7% and 73.3% for LEA, 88.4% and 91.1% for LNEA, 81.4% and 82.2% for OEA, 81.4% and 88.9% for PEA, 86.0% and 88.9% for SEA, respectively. Conclusion: Endocannabinoids are not useful in assessing pain in patients with chronic pancreatic diseases and they cannot replace a simple method such as VAS for assessing the pain and its intensity.