The relationship of postoperative cognitive dysfunction and brain injury biomarkers in geriatric urologic oncologic surgery

Objective: We aimed to evaluate the relationship between proinflammatory and neuronal damage biomarkers in geriatric patients, with postoperative cognitive dysfunction (POCD) and postoperative delirium (POD) in major urologic oncologic surgeries. Our secondary aims are to examine the relationship between regional cerebral oxygen saturations and postoperative complications and postoperative cognitive dysfunction. Materials and methods: Patients over 60 years of age who were scheduled for major abdominal surgery with the diagnosis of primary urological malignancy after the approval of the ethics committee (2019/1555) were included in this prospective observational study. Addenbrooke Cognitive Examination (ACE-R) was performed on the preoperative 1st day, postoperative 1st week, and 3rd month for the diagnosis of POCD. Patients with z>1.96 were diagnosed with POCD by subtracting the learning effect of a control group from the changes in the postoperative test scores compared to the preoperative test. Confusion Evaluation Method (CAM) was used in the diagnosis of POD. Blood samples were taken from the patients to determine the preoperative and postoperative serum levels of S-100β, NSE, IL-6 and HMGB1 by ELISA method. Results: Of the patients included in the study, 7 (13%) were female and 47 (87%) were male. The mean age of the patients was 73.7±7.1 years. POCD was observed in 17 (31.5%) patients after postoperatif first week and in 12 (22%) patients three months after the operation. POD was observed in 12 (22%) patients. Preoperative IL-6 (p<0.01), preoperative S-100β (p<0.01), postoperative IL-6 (p=0.01), and postoperative S-100β (p=0.03) serum levels were found to be significantly higher in POCD1 patients than non-POCD1 patients. Preoperative IL-6 (p=0.01) and preoperative S-100β (p=0.03) serum levels were found to be significantly higher in POCD3 patients than non-POCD3. Preoperative NSE (p=0.04) serum levels were found to be significantly higher in POD patients than non-POD. Conclusion: In geriatric major urological oncological surgeries, IL-6, which is an indicator of proinflammatory activity, and S-100, which is a neuronal damage biomarker, are associated with short- and long-term POCD; NSE, one of the neuronal damage biomarkers, was found to be associated with POD. These results support the idea that surgical trauma causes systemic inflammation which then causes a functional disruption in neural activity, leading to POCD and POD.