Background The contribution of regional anesthesia with thoracic paravertebral blockade to postoperative analgesia remains unclear. We compared the effect of a combination of paravertebral blockade and propofol general anesthesia (GA) with sevoflurane GA and opioid analgesia on postoperative pain and opioid use for patients undergoing breast cancer surgery. Methods Patients having breast cancer surgery were randomly assigned to paravertebral analgesia with propofol GA (PPA, n = 187) or sevoflurane GA with perioperative opioid analgesia (SOA, n = 199). The PPA and SOA groups were compared for opioid consumption and pain outcomes (on a 0-10 visual analogue scale [VAS]) at two hours postoperatively using superiority and inferiority statistics. We compared our results with previous publications in a meta-analysis. [0,12] mg, respectively, morphine equivalents; median difference -3; 99% CI: -4 to -2). Thus, non-inferiority was detected for all the above outcomes, and superiority tests for each outcome were highly significant in the expected directions (P \ 0.001). Meta-analysis, including the current study, estimated a reduction in worst pain of 2.3 points (95% CI: 1.8 to 2.8) on a 0-10 scale and a 72% reduction (95% CI: 42 to 87) in Conclusion Nos résultats ont été largement concordants avec des études antérieures beaucoup plus petites. Comparativement à l'AG au sévoflurane avec analgésie par opioïdes, l'association d'une analgésie paravertébrale et d'une AG au propofol a fourni des avantages cliniques précoces pour les femmes subissant une chirurgie pour cancer du sein. Cette analyse est une sous-étude d'un essai randomisé multicentrique à double insu sur la récidive cancéreuse (www.ClinicalTrials.gov: n8 NCT00418457).