Late sleep phase with respect to core body temperature rhythm is associated with a higher level of chemotherapy-induced peripheral neuropathy in patients with breast cancer

Chemotherapy-induced peripheral neuropathy (CIPN) is a prevalent adverse effect observed in cancer patients. This study aimed to investigate the impact of sleep phase within the biological clock on CIPN. The phase of the minimum core body temperature (CBTmin) was determined using a thermometer pill and the Munich Chronotype Questionnaire was employed to assess mid-sleep time (MSFsc), in 39 breast cancer patients. CIPN was evaluated at five time points using the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire-CIPN twenty-item scale. The late sleep phase group, whose MSFsc followed CBTmin, demonstrated higher scores on the square root-transformed sensory scale than the early sleep phase group, whose MSFsc preceded CBTmin, 9-month post-chemotherapy (p=0.001). A significant between-group difference in the global and motor scale score was observed across all time points (p=0.043, 0.026, respectively). Further research using a larger sample size may contribute to elucidating the role of sleep phase in the pathogenesis of CIPN.