Topical menthol for chemotherapy-induced peripheral neuropathy: a randomised controlled trial in breast cancer

Objectives Chemotherapy-induced peripheral neuropathy (CIPN) symptom is one of the side effects of paclitaxel in breast cancer patients. This randomised controlled study was conducted to investigate the effect of topical menthol applied on the hands and feet of breast cancer patients receiving chemotherapy on CIPN symptoms.Methods 60 breast cancer patients receiving chemotherapy were randomly assigned to an intervention group (n=30), which received topical menthol treatment, or a control group (n=30), which received standard care. Both groups continued their routine pharmacological treatments throughout the study. The intervention group applied 1% menthol topically to their hands and feet two times a day. The effect of the intervention on CIPN symptoms was evaluated 3 weeks and 6 weeks after the intervention.Results The intervention group showed a significantly greater improvement in CIPN symptoms over time compared with the control group, with an effect size of eta 2=0.214 for the groupxtime interaction. Additionally, the intervention group exhibited a notable positive change in the exposure subscale of the CIPN rating scale, with an effect size of eta 2=0.114.Conclusions Topical application of menthol significantly mitigates the symptoms of CIPN in breast cancer patients. This study supports the use of menthol as an effective adjunctive treatment for CIPN.Trial registration number NCT05429814.