Effect of hypnosis before general anesthesia on postoperative outcomes in patients undergoing minor surgery for breast cancer: a systematic review and meta-analysis.

Background: Preoperative anxiety is a common phenomenon in breast cancer, causing pain and tension, which is not conducive to the effective surgical treatment and postoperative recovery. It is believed that hypnosis can change the patient's perception of pain, thereby improving the patient's ability to control pain. However, the results of studies for this topic were controversy. In order to explore the effect of hypnosis in breast cancer surgery we included randomized controlled trials (RCTs) and conducted a meta analysis. Methods: PubMed, Web of Science, Wiley online library, Elsevier, and Clinicaltrials.gov databases were searched by computer with the keywords "hypnosis/hypnotherapy" and "breast cancer" and "oncologic surgery/surgery/biopsy". After screening, the meta-analysis was performed using RevMan 5.4 software, and the evidence was rated using GRADE profiler 3.6 software. Results: A total of 1,242 patients were included in 8 studies, including 630 patients who received preoperative hypnosis and 612 patients who did not receive hypnosis. Meta-analysis showed that hypnosis before general anesthesia reduced the degree of preoperative anxiety (MD =-2.79, 95% CI: -3.93, -1.65, P<0.00001) and postoperative pain (MD =-1.25, 95% CI: -1.64, -0.86, P<0.00001) in patients undergoing breast cancer surgery, but had no effect on the operation time (MD =-6.30, 95% CI: -15.38, 2.78, P=0.17) and the incidence of postoperative nausea and vomiting (OR =0.68, 95% CI: 0.22, 2.07, P=0.49). Discussion: The application of hypnosis before general anesthesia for breast cancer surgery can reduce the degree of anxiety of patients, also reducing postoperative pain.