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.