Effectiveness of Inhaled Aromatherapy on Chemotherapy-Induced Nausea and Vomiting: A Systematic Review

Background: Chemotherapy-induced nausea and vomiting (CINV) are among the most common and feared side effects of cancer treatments. Their presence has a negative impact on the quality of life and morbidity associated with the disease. Despite increasingly effective antiemetic treatments, 40% of cancer patients experience CINV during the acute or delayed phase of their treatment. This distressing experience lived through by a large number of people makes it a priority in the improvement of cancer patients and a daily concern for nurses in cancer care units. In an attempt to alleviate this problem, the idea of using aromatherapy as supportive care has led the authors to research the knowledge available on this subject. Objective: The purpose of this systematic review was to examine the existing scientific evidence regarding the effectiveness of respiratory aromatherapy on CINV in addition to standard treatment compared with their recommended management in people with cancer. Design: Systematic review. Methods: This review was conducted according to the preferred reporting items for systematic reviews and meta-analyses guidelines and queried six databases (PubMed, Scopus, Cochrane Database, Embase, CINAHL, and Google Scholar). An analysis of the risk of bias using the Cochrane "Risks of Bias" tools and a qualitative synthesis of the results of the studies were carried out. Results: Eleven studies were included, nine in adults and two in children. Seven out of nine studies showed statistically significant results in adults with either direct or dry inhalation. Four out of seven alleviated both nausea and vomiting thanks to peppermint, ginger essential oil; three decreased nausea only with chamomilla, ginger or cardamom essential oil. Atmospheric diffusion and the use of inhaled aromatherapy in children did not show any benefit. Conclusions: Results appear promising for the use of direct inhaled aromatherapy in the management of CINV. However, most of the studies found the women concerned suffered from gynecologic cancers and had certain methodological limitations. Indeed, small samples and a wide variety of interventions were studied (different essential oils, number of drops of essential oils used, method of administration, etc.), making it impossible so far to generalize these results. Studies with a more robust methodology and larger samples will make it possible to confirm the potential usefulness of this complementary treatment.