Understanding the level of fatigue in cancer patients undergoing radiotherapy.

This study tests the hypothesis that a discrepancy between resources and demands explains most of the variance in fatigue in cancer patients undergoing radiotherapy. Patients (n=250) were interviewed at pretreatment, posttreatment, and at 9-month follow-up. Resources involved physical condition, neuroticism, optimism, social support, gender, age, and level of education. Demands entailed prognosis, radiotherapy dose, the effort associated with actual activity, and the patient's perception of overall burden. Regression analyses were performed, using interaction terms to operationalize the discrepancy between resources and demands. The hypothesis was not supported. At pretreatment, physical condition explained most of the fatigue, whereas, at posttreatment, both the patients' physical condition and perception of burden contributed to fatigue. At follow-up, demands did not add to the variance already explained by resources, and vice versa. Factors that contribute to the patient's physical condition before starting radiotherapy and to his/her perception of burden need to be addressed to further our understanding of their fatigue.