Background and ObjectivesWe aim to evaluate the analgesic efficacy and safety of erector spinae plane block (ESPB) for postoperative analgesia in breast cancer surgeries. MethodsPubMed, Web of Science, CBM, Embase, Cochrane, Wanfang, VIPP, and CNKI were searched to identify published eligible randomized controlled trials. The primary results were the postoperative 24 h morphine consumption and pain scores, while the secondary outcomes included pain scores at other times, press times of patient-controlled intravenous analgesia (PCIA), times to request for first rescue analgesia, the incidence of request for rescue analgesia, opioid-related complications, nerve blocks related complications and patient satisfaction. ResultsWe included 20 studies meeting the inclusion criteria, which involved 1293 participants. The morphine consumption and the pain scores during 24 h postoperatively were significantly decreased in the ESPB group versus the control group (p < 0.00001). Furthermore, ESPB also reduced pain scores at other time points, press times of PCIA, and times to first rescue analgesia requirement. Meanwhile, there was a lower incidence of postoperative nausea and vomiting, and skin pruritus in the ESPB group than in the control group. ConclusionsCompared to general anesthesia alone, ESPB combined with general anesthesia can effectively reduce the postoperative pain intensity within 48 h and opioid consumption within 24 h after breast cancer surgery, and reduce the incidence of opioid and nerve blocks related complications.