Clinical analgesic efficacy of pectoral nerve block in patients undergoing breast cancer surgery A systematic review and meta-analysis

Background: Breast cancer is the most commonly diagnosed cancer in women, and more than half of breast surgery patients experience severe acute postoperative pain. This meta-analysis is designed to examine the clinical analgesic efficacy of Pecs block in patients undergoing breast cancer surgery. Methods: An electronic literature search of the Library of PubMed, EMBASE, Cochrane Library, and Web of Science databases was conducted to collect randomized controlled trials (RCTs) from inception to November 2018. These RCTs compared the effect of Pecs block in combination with general anesthesia (GA) to GA alone in mastectomy surgery. Pain scores, intraoperative and postoperative opioid consumption, time to first request for analgesia, and incidence of postoperative nausea and vomiting were analyzed. Results: Thirteen RCTs with 940 patients were included in our analysis. The use of Pecs block significantly reduced pain scores in the postanesthesia care unit (weighted mean difference [WMD] = -1.90; 95% confidence interval [CI], -2.90 to -0.91; P < .001) and at 24 hours after surgery (WMD = -1.01; 95% CI, -1.64 to -0.38; P < .001). Moreover, Pecs block decreased postoperative opioid consumption in the postanesthesia care unit (WMD = -1.93; 95% CI, -3.51 to -0.34; P = .017) and at 24 hours (WMD = -11.88; 95% CI, -15.50 to -8.26; P < .001). Pecs block also reduced intraoperative opioid consumption (WMD = -85.52; 95% CI, -121.47 to -49.56; P < .001) and prolonged the time to first analgesic request (WMD = 296.69; 95% CI, 139.91-453.48; P < .001). There were no statistically significant differences in postoperative nausea and vomiting and block-related complications. Conclusions: Adding Pecs block to GA procedure results in lower pain scores, less opioid consumption and longer time to first analgesic request in patients undergoing breast cancer surgery compared to GA procedure alone.