BACKGROUND In recent years, thoracic wall nerve blocks, such as the pectoral nerve (PECS) block and the serratus plane block have become popular for peri-operative pain control in patients undergoing breast cancer surgery. The effect of PECS block on quality of recovery (QoR) after breast cancer surgery has not been evaluated. OBJECTIVES To evaluate the ability of PECS block to decrease postoperative pain and anaesthesia and analgesia requirements and to improve postoperative QoR in patients undergoing breast cancer surgery. DESIGN Randomised controlled study. SETTING A tertiary hospital. PATIENTS Sixty women undergoing breast cancer surgery between April 2014 and February 2015. INTERVENTIONS The patients were randomised to receive a PECS block consisting of 30 ml of levobupivacaine 0.25% after induction of anaesthesia (PECS group) or a saline mock block (control group). The patients answered a 40-item QoR questionnaire (QoR-40) before and 1 day after breast cancer surgery. MAIN OUTCOME MEASURES Numeric Rating Scale score for postoperative pain, requirement for intra-operative propofol and remifentanil, and QoR-40 score on postoperative day 1. RESULTS PECS block combined with propofol-remifentanil anaesthesia significantly improved the median [interquartile range] pain score at 6 h postoperatively (PECS group 1 [0 to 2] vs. Control group 1 [0.25 to 2.75]
P=0.018]. PECSblock also reduced propofol mean (± SD) estimated target blood concentration to maintain bispectral index (BIS) between 40 and 50 (PECS group 2.65 (± 0.52) vs. Control group 3.08 (± 0.41)μgml-1
P&lt
0.001) but not remifentanil consumption (PECS group 10.5 (± 4.28) vs. Control group 10.4 (±4.68)μgkg-1 h-1
P=0.95). PECS block did not improve the QoR-40 score on postoperative day 1 (PECS group 182 [176 to 189] vs. Control group 174.5 [157.75 to 175]). CONCLUSION In patients undergoing breast cancer surgery, PECS block combined with general anaesthesia reduced the requirement for propofol but not that for remifentanil, due to the inability of the PECS block to reach the internal mammary area. Further, PECS block improved postoperative pain but not the postoperative QoR-40 score due to the factors that cannot be measured by analgesia immediately after surgery, such as rebound pain.