Purpose: To assess the level of fatigue during the course of adjuvant radiotherapy (RT) of breast cancer patients and its relation to anxiety, depression, serum cytokines, and blood count levels.
Methods and materials: Forty-one patients who received adjuvant RT after breast-conserving surgery were prospectively studied. All patients underwent RT without concomitant chemotherapy. Patients rated their fatigue with two standardized self-assessment instruments, the Fatigue Assessment Questionnaire and a visual analog scale on fatigue intensity, before RT, during weeks 1-5 of RT, and 2 months after RT completion. In addition, the anxiety and depression levels were assessed with the Hospital Anxiety and Depression Scale. A differential blood cell count and the serum levels of the cytokines interleukin (IL)-1beta, IL-6, and tumor necrosis factor-alpha were determined in parallel to the fatigue assessments.
Results: Fatigue intensity as assessed with the visual analog scale increased (p <0.001) until treatment week 4 and remained elevated until week 5. Two months after RT, the values had fallen to the pretreatment levels. Fatigue measured with the Fatigue Assessment Questionnaire did not increase significantly during treatment, but the subscores on physical (p = 0.035) and cognitive (p = 0.015) fatigue were elevated during treatment weeks 4 and 5. Affective fatigue did not change significantly. Anxiety, as rated with the Hospital Anxiety and Depression Scale, declined during RT (p = 0.002), but the Hospital Anxiety and Depression Scale depression score did not change significantly. IL-1beta, IL-6, and tumor necrosis factor-alpha levels did not change during therapy and did not correlate with fatigue. Peripheral blood cell levels declined significantly during therapy and were still low 2 months after treatment. Until treatment week 5, lymphocytes were reduced to almost 50% of their initial values. Hemoglobin levels did not correlate with fatigue.
Conclusions: We observed an increase in fatigue during adjuvant RT of patients with breast cancer. Fatigue returned to pretreatment levels 2 months after treatment. No evidence was found that anxiety, depression, serum levels of IL-1beta, IL-6, tumor necrosis factor-alpha, or declining hemoglobin levels were responsible for the treatment-induced fatigue.