Auricular therapy for chemotherapy-induced nausea and vomiting in cancer patients: current evidence and directions for future research and practice

Background: Auricular therapy (AT) has been historically viewed as a convenient non-pharmacological approach for cancer patients with chemotherapy-induced nausea and vomiting (CINV). However, the effect of AT for CINV is still uncertain.

Purpose: To assess the evidence of the therapeutic effect of AT for CINV in cancer patients, to identify limitations from current practice, as well as to provide recommendations for developing a future AT protocol used for managing CINV.

Methods: Relevant randomized controlled trials were searched and retrieved from 12 databases (PubMed, EMBase, CENTRAL, CINAHL, AMED, PsyclNFO, ISi Web of Science, Science Direct, CNKI, WanFang Data, VIP, and CBMdisc) without language restrictions. Meanwhile, manual search was conducted for Chinese journals on complementary medicine published within the last five years, and the reference lists of included studies were also checked to identify any possible eligible studies. The Cochrane collaboration's tool for risk of bias was utilized to evaluate the methodological quality of included trials, and descriptive analysis was employed to summarize the therapeutic effect of AT for both primary and secondary outcomes.

Results: Twenty-one studies with 1713 participants were included. The methodological quality of the analyzed trials was generally unsatisfactory. Among all the analyzed studies, the effect rate of AT for managing acute CINV ranged from 44.44% to 93.33% in the intervention groups and 15% to 91.67% in the control groups. For delayed CINV, it was 62.96% to 100% and 25% to 100% respectively. In addition to the primary outcome of CINV, AT was also shown to be effective in improving the patients' physical performance status as well as relieving anxiety and depression.

Conclusion: AT seems to be a promising approach in managing CINV with encouraging results reported in previous studies. However, the level of evidence was low and the definite effect cannot be concluded as there were significant methodological flaws identified in the analyzed studies. The implications drawn from the 21 studies present some clues for developing a future evidence-based AT protocol for CINV management, as well as provides some recommendations for future research in this area including the need to conduct more rigorously designed randomized controlled trials.