The Correlation Between Neoadjuvant Chemotherapy for Ovarian Cancer and the Analgesic Effects of Remifentanil a Prospective Cohort Study

Background: Neoadjuvant chemotherapy (NACT) is a key therapy for ovarian cancer that reduces tumor burden but injures normal tissues, necessitating meticulous anesthesia management. However, the pharmacokinetics and pharmacodynamics of remifentanil, a commonly used anesthetic analgesic, in this context remain inadequately studied, and relevant research in this patient population remains insufficient. Purpose: This prospective observational cohort study aimed to evaluate the effect of preoperative NACT on intraoperative remifentanil requirements in ovarian cancer patients and assess perioperative outcomes to guide its rational clinical use. Methods: Seventy ovarian cancer patients undergoing surgery were divided into NACT (3 to 4 cycles of paclitaxel + carboplatin) and Non-NACT groups; 64 completed the study. The plasma concentration of remifentanil was titrated to maintain the intraoperative Index of Consciousness 2 (IOC2) value between 35 and 45. The primary outcome was average intraoperative remifentanil consumption; secondary outcomes included intraoperative and postoperative hemodynamic indicators, usage of vasoactive drugs, incidence of adverse events, and postoperative recovery indicators. Results: Compared with the Non-NACT group, the NACT group had significantly higher intraoperative remifentanil consumption [11.89 ± 2.02 vs. 9.40 ± 1.81 μg·kg − 1 ·h − 1 , p < 0.001] and target concentration adjustment frequency [3.97 (1.62) vs. 2.75 (1.32), p=0.002]. Intraoperative heart rate (HR) and mean arterial pressure (MAP) were significantly higher in the NACT group at T3, T4, and T5 (all p< 0.05). Specifically, HR at T3 [89.47 (12.00) vs. 81.56 (14.98), p=0.02], T4 [70.88 (9.20) vs. 64.53 (12.89), p=0.03], T5 [72.94 (12.86) vs. 64.31 (13.08), p=0.01]; MAP at T3 [122.80 (11.67) vs. 114.18 (12.48), p=0.01], T4 [103.16 (11.26) vs. 95.72 (8.87), p=0.01], T5 [107.27 (12.38) vs. 99.91 (10.46), p=0.01]. Conclusion: Preoperative NACT increases ovarian cancer patients’ sensitivity to intraoperative pain, leading to higher remifentanil consumption and more frequent concentration adjustments. Clinically, higher intraoperative analgesic doses are needed for adequate pain control in this population. Keywords: ovarian cancer, NACT, opioids, remifentanil, index of consciousness 2, IOC2, intraoperative analgesia