Effect of Opioid-Free General Anesthesia Versus Opioid-Based General Anesthesia on Postoperative Pain and Immune Response in Patients Undergoing Breast Cancer Surgery: A Randomized Controlled Trial

Perioperative opioids are associated with several adverse effects including nausea, vomiting, and long-term addiction. Opioid-free anesthesia may reduce postoperative morbidity, enable daycare surgery, and decrease cancer recurrence. In our study, we aimed to assess the efficacy of opioid-free anesthesia versus opioid-based anesthesia in patients undergoing breast cancer surgery in terms of postoperative opioid use, pain scores, expression of immune cells, and side effects. Hundred patients undergoing breast cancer surgery were randomized into two groups (1:1 ratio). Group O received opioid-based anesthesia and Group N did not receive any opioid intraoperatively. Our primary outcome was total postoperative morphine consumption in 24 h managed with a patient-controlled analgesia (PCA) pump containing morphine in both groups. Secondary outcomes were numerical rating scale (NRS) at rest and movement at immediate postoperative period, 30 min, 1 h, 2 h, 6 h, and 24 h postoperatively was measured. Blood samples were also taken at different time points to measure inflammatory markers. There was no statistical difference in the total 24 h postoperative morphine consumption in between the two groups (p = 0.13). The patient satisfaction scores and NRS at rest and on movement at various time points postoperatively were similar (p > 0.05). There was a significant difference in neutrophil lymphocyte ratio (NLR) between the two groups in the samples taken at 24 h postoperative period (p = 0.03). No complications were reported in any group. While our study did not show opioid-free anesthesia’s superiority in postoperative morphine consumption, it established the feasibility and safety of a non-opioid technique for breast cancer surgery. The approach may offer advantages, including potential immunosuppression relief, making it a viable option for patients prone to opioid-related side effects.