The Impact of Paravertebral Block Analgesia on Breast Cancer Survival After Surgery. Cata JP, Chavez-MacGregor M, Valero V et al. Reg Anesth Pain Med. 2016 Nov/Dec;41(6):696-703.   Seven hundred ninety-two women with nonmetastatic breast cancer were included in this retrospective study. Patients were divided based on the administration of PVB analgesia for mastectomy surgeries.