Effect of Perioperative Lidocaine or High-Dose Dexamethasone on Immune Response in Colon Cancer Surgery (PILDI Study)

This study is a prospective, randomized, double-blind, controlled phase II interventional clinical trial conducted at the Institute of Oncology Ljubljana. The trial investigates the effects of two perioperative pharmacological interventions-intravenous lidocaine infusion and high-dose dexamethasone-on postoperative immune response and clinical outcomes in patients undergoing surgical treatment for colon cancer. Patients undergoing major oncologic surgery may develop significant perioperative immune suppression and inflammatory responses, which can influence postoperative recovery, complication rates, and overall outcomes. Lidocaine is known to have potential anti-inflammatory and immunomodulatory effects, while dexamethasone is widely used perioperatively for its anti-inflammatory properties. However, comparative evidence regarding their impact on postoperative immune response in colorectal cancer surgery is limited. Eligible participants are adult patients with histologically confirmed colon cancer who are scheduled for surgical resection. After providing written informed consent, participants will be randomized in a double-blind manner to one of two study groups: Perioperative intravenous lidocaine infusion group High-dose perioperative dexamethasone group Both interventions are administered according to the study protocol during the perioperative period. Randomization and masking ensure that participants, investigators, and clinical staff remain blinded to treatment allocation. The primary objective of the study is to evaluate differences in postoperative immune response between the two intervention arms, assessed through laboratory immune and inflammatory markers. Secondary objectives include evaluation of postoperative clinical outcomes, such as postoperative recovery parameters and complications. Participants are followed during the perioperative period and after surgery, and study assessments are performed according to the predefined schedule. This study will provide evidence regarding whether perioperative lidocaine infusion may offer beneficial immunological or clinical effects compared with high-dose dexamethasone in patients undergoing surgery for colon cancer. The results may support improved perioperative supportive care strategies and optimization of postoperative recovery in oncologic surgical patients.