The association between the circadian misalignment of serum cortisol acrophase and sleep end time with chemotherapy-induced peripheral neuropathy

Chemotherapy-induced peripheral neuropathy (CIPN) is a common adverse effect of chemotherapy. The objective of this prospective observational study was to examine the association between circadian misalignment (CM), as measured by phase angle difference (PAD) of biological and behavioral rhythms and CIPN. The PAD of cortisol acrophase and actigraphy-based sleep end time in breast cancer patients was measured and categorized into low PAD (<i>n</i> = 11) and high PAD (<i>n</i> = 12) groups based on median value. CIPN was assessed using the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire-CIPN20 (CIPN20). The assessment of CM revealed that the sleep end time of the low PAD group was more delayed in relation to cortisol acrophase compared to the high PAD group. The low PAD group demonstrated significantly higher CIPN20 global and sensory scale scores compared to the high-PAD group at one month post-chemotherapy, with an estimated group difference of 17.63 ± 4.75 and 27.07 ± 6.70 (<i>p</i> = 0.001 and <i>p</i> < 0.001, respectively). The present findings indicate that the low PAD group, which exhibited a relatively delayed behavioral rhythm with respect to its biological rhythm, displayed an increased susceptibility to CIPN. Further large-sample research is necessary to attain a comprehensive understanding of the mechanisms through which CM affects CIPN.