Aromatherapy with single essential oils can significantly improve the sleep quality of cancer patients: a meta-analysis

Objective To investigate the effect of aromatherapy on sleep quality in cancer patients. Methods Published literature on the effect of aromatherapy in cancer patients with sleep disorders in the form of randomized controlled trials (RCTs) were systematically retrieved and screened from PubMed, Cochrane Library, Embase, CBM, CNKI, VIP, and Wanfang databases from inception to November 2021. The methodological quality of the included studies was critically and independently evaluated by two reviewers using the Cochrane Risk of Bias Assessment Tool for RCTs. The correlated data were extracted using the pre-designed form, and all analyses were performed using Reviewer Manager version 5.4. Due to the difference in sleep quality instruments, the data extracted in this study were in the form of standard mean difference (SMD). Results Ten RCTs included 933 patients (experimental group: 474, control group: 459), and the risk of bias in the included studies was moderate. Aromatherapy could significantly improve the sleep quality of cancer patients [SMD = − 0.79, 95% CI (− 0.93, − 0.66), p < 0.01], especially those with breast cancer [SMD = − 0.98, 95% CI (− 1.57, − 0.40), p < 0.01]. Aromatherapy with single essential oil had a better effect on sleep quality [SMD = -0.94, 95%CI (− 1.25, − 0.62), p < 0.01], of which lavender essential oil had the best effect [SMD = -1.06,95%CI (− 1.49, − 0.63), p < 0.01] while compound essential oils had no effect on sleep quality improvement in cancer patients [SMD = -0.21, 95%CI (− 0.57, 0.14), p = 0.23]. Four of the ten RCTs reported the occurrence of adverse events, of which only one RCT indicated that patients had headache and sneezing while the remaining six did not. Conclusions This meta-analysis of 10 RCTs reveals that aromatherapy with single essential oil had a substantial effect on the sleep quality of cancer patients and should be recommended as a beneficial complementary therapy to promote sleep quality in cancer patients.