Patients with chemotherapy-induced peripheral neuropathy (CIPN) experienced similar effects from a 6-week essential oil intervention (EOI) as with a placebo, a pilot study published in Pain Management Nursing shows. However, the investigators report that, while both placebo and EOI-treated patients experienced pain score reductions from baseline through 2 hours following treatment before a gradual return toward baseline — EOI-treated patients saw a significantly greater reduction in mean pain compared with placebo-treated patients.
Investigators conducted the convergent-parallel, single-blind, randomized, placebo-controlled trial between 2018 and 2019. Breast cancer survivors (N=26 women; age range, 37-75 years; 54% Black) with CIPN in both lower extremities 3 months after completing chemotherapy were randomly assigned to receive essential oil (n=13) or placebo (n=13) for 6 weeks packaged in 5 mL doses.
The participants were asked to cover their lower extremities from tibial tubercle to phalanges every 8 hours. The active intervention was handcrafted to contain half Simmondsia chinensis and half essential oils comprising turmeric, peppermint, geranium, rose, black pepper, rosemary, ginger, and jojoba.
The study outcomes were the change to Short-Form McGill Pain Questionnaire-2 (SF-MPQ-2), visual analogue scale (VAS) score for pain, Quality of Life Chemotherapy-Induced Peripheral Neuropathy-20 Questionnaire (QOL:CIPN-20), and Quality of Life Adult Cancer Survivor Questionnaire (QLACS).
At baseline, the participants endorsed using gabapentin (31%), over-the-counter topical medications (19%), duloxetine (8%), pregabalin (8%), tramadol (8%), cyclobenzaprine (8%), acetaminophen (4%), aspirin (4%), ibuprofen (4%), cannabidiol oil (4%), or hydroxyzine (4%), or a combination, for pain relief.
The researchers report significant changes in SF-MPQ-2 scores during the study. They found the week of treatment significant (c2, 25.063; P <.001) but not group (P =.178) or group-by-week interaction (P =.480).
The VAS pain scores decreased during the study among the essential oil recipients, but not among participants in the control group; however, week (P =.318), group (P =.310), and the group-by-week interaction (P =.196) were not significant. The study shows a significant effect of education on VAS outcomes (c2, 4.169; P =.041).
Both groups reported improved quality of life outcomes, but no group difference was found (P =.885). The research shows that age has a significant effect for the subdomain of negative feelings (P =.002).
Of clinical importance, the investigators did find patients treated with the EOI experienced a 40% reduction in mean pain from baseline to 2 hours, compared with the participants in the placebo group, who experienced a 24.6% reduction in the same timeframe.
“Two participants contacted the researcher after the study and provided feedback related to the emotional effects of the EOI and placebo. One intervention group participant had a significant reduction in pain over six weeks and reported missing the smell of the EOI because it had become reassuring and comforting to her. Researchers should consider olfactory-related responses a priori,” the investigators report.
The major limitation of this study was that the target sample size was not met due to poor recruitment.
These data indicate that an essential oil intervention is feasible for the treatment of CIPN among breast cancer survivors, but the researchers say little evidence of efficacy compared with placebo exists.
Langley-Brady DL, Campbell RT, Maihle NJ, Barnes VA, Bratton AR, Zadinsky JK. A pilot randomized controlled trial evaluating essential oils for chemotherapy-induced peripheral neuropathy. Pain Manag Nurs. 2023;S1524-9042(22)00226-0. doi:10.1016/j.pmn.2022.12.008