Fatigue, self-efficacy, and physical functional status in persons with lung cancer

Cancer-related fatigue (CRF) is a prevalent and severe symptom that is inadequately managed and accompanied by other unpleasant symptoms that negatively impact the physical functional status (PFS) of persons with cancer and especially those with lung cancer (LC). Symptom management occurs through self-directed action, with perceived self-efficacy (PSE) being a key factor. Existing theories and studies do not address the key role PSE plays in a person's ability to manage symptoms and improve their PFS, making the current study unique in persons with LC and other cancer (OC) diagnoses.; Secondary data analyses from baseline observation of two randomized control trials were performed on 63 persons with LC and 235 persons with OC diagnoses who were undergoing a course of chemotherapy. For the total sample and in the LC and OC groups separately, the hypothesis of mediation from CRF to PFS through PSE for fatigue management was tested showing significant support for partial mediation. In the total sample, the magnitude of the relationship between CRF and PFS was reduced after PSE for fatigue management was controlled, with the mediation accounting for 12% of the variance (t = -2.59; p = .009). Consequently, CRF severity directly influences PFS and indirectly influences PFS by its effect on PSE for fatigue management. Further, on a 0-10 scale (10 = most severe), similar levels of CRF severity were reported by persons with LC (M = 5.88; SD = 2.00) and OC (M = 5.83; SD = 2.29) diagnoses (t = -.161; df = 296; p = .872). However, through blockwise, hierarchical multiple regression, similar levels of CRF severity were found to significantly worsen the PFS of persons with LC as compared to OC diagnoses (t = -3.78). In addition to type of cancer diagnoses, five other factors in the total sample were identified through blockwise, multiple hierarchical regression as the most important factors accounting for 47.7% of the explained variance in PFS [F (28, 295) = 8.68, p = .000]. Specifically, higher levels of PSE for fatigue management (t = 3.55) were found to be one of the strongest predictors of greater PFS, while lower levels of PFS were predicted by greater total CRF severity (t = -5.39), greater number of co-morbid conditions (t = -4.20), greater total symptom severity (t = -2.46), and having surgery prior to chemotherapy (t = -2.31).; Lower levels of PSE for fatigue management were identified through best of all subset regression to be a predictor of greater CRF severity in the total sample and in the LC and OC groups. Persons with LC (M = 4.99; SD = 1.43) as compared to OC (M = 4.54; SD = 1.60) diagnoses reported higher levels of total severity of the other unpleasant symptoms (t = -1.99; df = 294; p = .047). Through path analyses, the CRF severity had a direct effect on increasing the total symptom severity of the other unpleasant symptoms (t = 9.69) which lowered the PFS (t = -2.71) for persons with LC and OC diagnoses.; The findings indicate that CRF is related to the presence of other symptoms, and PSE is an important factor in optimizing CRF management and PFS. This study provides the foundation for future intervention studies to increase PSE to achieve optimal symptom management and PFS in persons with cancer.