Effect of intravenous lidocaine on chronic postoperative pain in patients undergoing breast cancer surgery: a prospective, double-blind, randomized, placebo-controlled clinical trial

Chronic postoperative pain (CPSP) is one of the common complications of breast cancer patients, which can seriously affect the quality of life and long-term prognosis of patients. The purpose of this study was to investigate whether perioperative intravenous lidocaine infusion could reduce the incidence of CPSP in patients with breast cancer.Female patients undergoing radical breast cancer surgery were randomly assigned to the 2% lidocaine group (L) and the control group (S). group L received an intravenous infusion of 1.5 mg/kg lidocaine 10 minutes prior to induction, followed by a continuous infusion of 2 mg/kg/h until the end of surgery. The control group received an equal amount of saline. The primary outcome was the incidence of CPSP at 3 months. Secondary outcomes included VAS pain scores and frequency of remedial analgesia within 24 hours postoperatively; incidence of CPSP at 1 and 6 months; and scores on the Brief Pain Inventory (BPI), Simplified McGill Pain Questionnaire (SF-MPQ), and Neuropathic Pain Score (DN-4) at 1, 3, and 6 months postoperatively.Eighty-two patients participated in this study. A total of 78 patients completed the 3-month postoperative follow-up (39 in group S and 39 in group L). At 3 months, the incidence of CPSP was significantly lower in the L group than in the S group (33.3% in the S group and 12.8% in the L group, P=0.032). Pain scores at rest and during exercise were significantly lower in the L group than in the S group at different time points (P≤0.001 and P<0.001). The need for remedial analgesia at 24 hours postoperatively also differed significantly between the two groups (P=0.036). At 6 months, the incidence of CPSP was also lower in the L group than in the S group (29.7% in the S group and 10.5% in the L group, P=0.038). The differences in SF-MPQ scores were statistically significant at both 3 and 6 months postoperatively (P=0.022, P=0.037).Intravenous infusion of lidocaine reduces the incidence of CPSP in breast cancer patients at 3 and 6 months and is effective in relieving acute postoperative pain.Chinese Clinical Trial Registry ChiCTR2100050445.