Abstract
INTRODUCTION: One out of seven women will develop a state of chronic postoperative pain following robot-assisted hysterectomy for endometrial cancer. Recently, metabolic studies have indicated that circulating lipids and lipoproteins could act as nociceptive modulators and thereby influence the induction and perpetuation of pain. The objectives of this explorative study were (1) to examine the preoperative serologic variations in concentrations of lipids, lipoproteins, and various low-molecular metabolites in patients with and without chronic postoperative pain after robot-assisted hysterectomy and (2) to explore if any of these serological biomarkers were predictive for development of chronic postoperative pain. MATERIALS AND METHODS: The study was designed as a nested case-control study within a cohort of women treated for endometrial cancer with robot-assisted laparoscopic hysterectomy. Twenty-six women with chronic postoperative pain were matched on age and body mass index with fifty-two controls without chronic postoperative pain, and metabolic profiling of preoperatively drawn blood samples from a biobank was performed by means of nuclear magnetic resonance spectroscopy. RESULTS: Nineteen metabolites, including cholesterol, cholesteryl ester, linoleic acid, phospholipids, lipids, and triglycerides had statistically significant higher concentrations in a subgroup of patients who would develop chronic postoperative pain on a later stage compared to the group of patients who would not develop chronic postoperative pain (p < 0.05). A sparse Partial Least Squares-Discriminant Analysis model explained 38.1% of the variance and had a predictive accuracy of 73.1%. CONCLUSIONS: This explorative study substantiates the hypothesis that certain lipids, lipoproteins, and fatty acids are associated with chronic postoperative pain.