Chronic, self-reported fatigue in adult immunotherapy patients and healthy controls: No association with cardiopulmonary exercise testing parameters.
This study examined whether cardiopulmonary exercise test (CPET) performance parameters are associated with chronic cancer-related fatigue in patients receiving immunotherapy checkpoint inhibitors (ICI) and healthy controls. Also, the differences in energy expenditure of steady-state cycling and gross efficiency were assessed during submaximal cycling efforts. This study involved patients (n = 19, 48 ± 13 years) receiving PD-1, PD-L1 checkpoint inhibitors and controls of similar age (n = 21, 49 ± 17 years). During the first visit, data on medical history, previous physical activity records, and CPET to voluntary exhaustion were collected. The second visit involved body composition assessment, the MFI-20 fatigue questionnaire, and 30-min steady-state cycling at 90% gas exchange threshold. There were no significant differences observed between the groups in age, stature, BMI, or resting blood pressure. Peak V̇O2 was 33% lower, and the group under ICI treatment had lower cycling efficiency (22.49% vs. 20.07%, p = 0.031), compared to controls. All self-reported fatigue items derived from MFI-20 were significantly higher in the ICI group compared to controls (p = 0.001). The regression analysis found no association between the self-reported general fatigue and data collected during CPET. Patients under ICI treatment reported higher levels of chronic fatigue, lower peak V̇O2, and reduced cycling efficiency. Interestingly, variables collected during CPET did not explain self-reported chronic fatigue, underlying the complexity of this phenomenon.