Non-pharmacological treatments for anticipatory nausea and vomiting during chemotherapy: a systematic review and meta-analysis of the Clinical Practice Guidelines for Antiemesis 2023

Background: Anticipatory chemotherapy-induced nausea and vomiting (CINV) is a conditioned response influenced by the severity and duration of previous emetic responses to chemotherapy. We aimed to evaluate the efficacy of non-pharmacologic interventions for anticipatory CINV among patients with cancer. Methods: We conducted a systematic search in databases, including PubMed, the Cochrane Library, CINAHL, and Ichushi-Web, from January 1, 1990, to December 31, 2020. Randomized controlled trials, non-randomized designs, observational studies, or case–control studies that utilized non-pharmacological therapies were included. The primary outcomes were anticipatory CINV, with an additional investigation into adverse events and the costs of therapies. The risk-of-bias for each study was assessed using the Cochrane risk-of-bias tool, and meta-analysis was performed using Revman 5.4 software. Results: Of the 107 studies identified, six met the inclusion criteria. Three types of non-pharmacological treatments were identified: systematic desensitization (n = 2), hypnotherapy (n = 2), and yoga therapy (n = 2). Among them, systematic desensitization significantly improved anticipatory CINV as compared to that in the control group (nausea: risk ratio [RR] = 0.60, 95% confidence interval [CI] = 0.49–0.72, p < 0.00001; vomiting: RR = 0.54, 95% CI = 0.32–0.91, p = 0.02). However, heterogeneity in outcome measures precluded meta-analysis for hypnotherapy and yoga. Additionally, most selected studies had a high or unclear risk of bias, and adverse events were not consistently reported. Conclusions: Our findings suggest that systematic desensitization may effectively reduce anticipatory CINV. However, further research is warranted before implementation in clinical settings.