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

BACKGROUND: 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. METHODS: 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. RESULTS: 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). CONCLUSIONS: 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. TRIAL REGISTRATION: Chinese Clinical Trial Registry ChiCTR2100050445.