A second study done with 73 women receiving adjuvant radiation therapy for breast cancer found similar differences in the patterns and predictors of morning versus evening fatigue. Participants were recruited to the study at the time of their simulation visit and completed baseline questionnaires. Data were then collected on 2 subsequent days, in the morning and at bedtime, each week during radiation therapy; every 2 weeks for 2 months after radiation therapy; and once a month for 2 additional months thereafter. Fatigue was measured with the Lee Fatigue Scale. For the group as a whole, over the 25 weeks of data collection, morning fatigue decreased slightly during radiation therapy and was constant for 4 months afterwards, while evening fatigue increased through radiation therapy and then declined slightly after treatment. Evening fatigue was higher for those who:
- Were working.
- Had children at home.
- Had higher depression scores.
Morning fatigue was higher for those who:
- Had more trait anxiety.
- Were experiencing sleep disturbance.
- Were younger.
- Had lower body mass indices.
Advanced disease and comorbidities also added to the severity of morning fatigue.[Level of evidence: III]
A number of research studies document the existence of a fatigue syndrome that is not specific to the disease type or radiation site and that demonstrates a gradual decline in fatigue in the patient after treatment is completed.[15,17,18,19,20] Some of these studies suggest, however, that not all patients return to pretreatment energy levels. Specific etiologic factors and correlates of fatigue associated with radiation therapy have not been identified. Risk factors for persistent low energy in cancer patients include older age, advanced disease, and combination-modality therapy.
Fatigue is a dose-limiting toxicity of treatment with a variety of biotherapeutic agents. Biotherapy exposes patients with cancer to exogenous and endogenous cytokines. Biotherapy-related fatigue usually occurs as part of a constellation of symptoms called flulike syndrome. This syndrome includes fatigue, fever, chills, myalgias, headache, and malaise. Mental fatigue and cognitive deficits have also been identified as biotherapy side effects. The type of biotherapeutic agent used may influence the type and pattern of fatigue experienced.