THE ASSOCIATION BETWEEN CIRCADIAN DISRUPTION IN CORE BODY TEMPERATURE RHYTHM AND POST-CHEMOTHERAPY SLEEP DISTURBANCES IN BREAST CANCER SURVIVORS

초록

Introduction: Sleep disturbance is a common symptom experienced by approximately 70% of breast cancer survivors and persists after the conclusion of chemotherapy. The relationship between core body temperature (CBT) and sleep disturbance with regard to sleep latency has been investigated in healthy individuals, yet remains unstudied in breast cancer patients. This study aimed to quantify the circadian disruption of the CBT rhythm and its correlation with sleep disturbance following chemotherapy. Methods: In a sample of 25 breast cancer survivors, CBT was measured using an ingestible thermometer pill to calculate the relative amplitude (RA) prior to chemotherapy (T0). The remaining circadian variables of the CBT rhythm were evaluated through the implementation of nonparametric and cosinor analyses. The Pittsburgh Sleep Quality Index (PSQI) was employed to assess global sleep quality at three time points: prior to the commencement of chemotherapy, at one month (T1), and nine months (T2) following the conclusion of chemotherapy. Subjective and objective sleep latency (SLs and SLo) were measured using the PSQI and actigraphy, respectively. Results: The low RA group exhibited higher intradaily variability of CBT (p<0.001) and a higher average temperature of the lowest 5-hour period in comparison to the high RA group (p=0.027). The low RA group exhibited lower global sleep quality than the high RA group at both time points (T1 and T2). SLs in the low RA group was significantly longer compared to the high RA group at both time points. Furthermore, the discrepancy in SL (∆SLs–SLo) demonstrated a notable between-group difference at both time points. Conclusion: The findings of this study suggest that breast cancer survivors with pronounced circadian disruption of the CBT rhythm prior to chemotherapy are more prone to sleep disturbances following chemotherapy. Additionally, prolonged SLs may be a contributing factor to their poor sleep quality.