Comparison between subjective and objective fatigue in patients with lung cancer and cancer-free participants: Evaluation of diagnostic criteria for cancer-related fatigue. Journal of Clinical Oncology

440Background: Cancer-related fatigue is one of the most distressing symptoms of cancer patients. Finding a patient's fatigue often requires the use of a subjective assessment scale, such as the Brief Fatigue Inventory (BFI). There are few objective ways to measure fatigue. The aim of this study was to evaluate whether objective cancer-related fatigue (CRF) diagnostic criteria can differentiate cancer from cancer-free participants and to explore the relationship between subjective and objective fatigue. Methods: In this study, we used a photoplethysmography (PPG) smartband device to collect the PPG information from the patients. During PPG measurements, the heart rate variability (HRV) signal was included in the data collection process for subsequent calculation of the LF/HF ratio. Participants completed a self-report measure to assess demographics, fatigue levels, and brief sleep diaries for the next 7 days. At the same time, the participants wore a wristband to collect HRV signals, which triggered HRV every hour over a 24-hour period for 7 consecutive days. Results: Cancer patients (n = 71) and cancer-free controls (n = 75) were studied. Study participants completed CRF questionnaires and heart rate variability (HRV) records. The smartband can be worn continuously for 120 hours as an objective measure of activity phase, sleep phase and HRV. Compared with controls, cancer patients were more fatigued and were more likely to be disturbed by fatigue (t = -3.73, p < 0.001), especially general activity (t = -2.93, p < 0.001), walking ability (t = -3.6, p < 0.001) and normal work (t = -2.18, p = 0.03). Wearing the bracelet can get the LF/HF value of HRV in the time domain. The LF to HF and LF/HF disorder ratios were further divided into active and sleep phases. During sleep phase, the LF/HF disorder ratio was higher in the cancer group than in the control group regardless of whether fatigue was mild or moderate (t = -2.5, p = 0.01; t = -2.8, p = 0.01, respectively). The LF/HF disorder ratios was higher in cancer patients with mild fatigue than in cancer-free participants during sleep phase (40% vs 20%, respectively). Cancer patients with moderate fatigue had higher incidence of LF/HF disorder ratios than cancer-free participants (50% vs 20%, respectively). Conclusions: It can be concluded that the diagnostic criteria of subjective and objective CRF can distinguish cancer and cancer-free cases. Using this objective fatigue device could provide an indicator for further clinical monitoring. Clinical trial information: NCT04300842.