Cancer-Related Fatigue: Approach to Assessment and Management

Assessment of Contributing Factors

The management of fatigue should be multifactorial, with a comprehensive assessment and treatment plan to address all modifiable fatigue etiologies. The Table lists potential contributing factors to fatigue that should be considered when evaluating patients for CRF; several common conditions are discussed below.

Anemia. Anemia has been correlated with fatigue and quality of life. In a study of 4382 cancer patients receiving chemotherapy, quality-of-life measures using FACT-Anemia scores improved with increased hemoglobin levels.³⁸ Cancer patients may have anemia due to marrow-suppressing effects of chemotherapy and may also have iron deficiency anemia due to blood loss or auto-immune hemolytic anemia. Therefore, a detailed work-up is required to identify the etiology of anemia. Patients with CRF whose anemia is related to chemotherapy or anemia of chronic disease may benefit from red blood cell transfusion or erythropoiesis-stimulating agents (ESAs). ESAs have been studied extensively; however, their use is controversial because of concerns about thromboembolic side effects leading to adverse outcomes.³⁹ Also, ESA therapy is not recommended in patients with hematologic malignancies. ESA use should be restricted to patients with chemotherapy-related anemia with hemoglobin below 10 mg/dL and should be discontinued in 6 to 8 weeks if patients do not respond.⁴⁰ Other patients may benefit from blood transfusions, which were shown to help in patients with hemoglobin levels between 7.5 and 8.5 g/dL.⁴¹

Sleep disturbance. Poor sleep is common in fatigued cancer survivors.⁴² Pro-inflammatory cytokines can disrupt the sleep–wake cycle, causing changes in the HPA axis and neuro­endocrine system, which in turn may lead to increasing fatigue. Heckler et al showed that improvement in nighttime sleep leads to improvement of fatigue.⁴³ Cognitive behavioral therapy and sleep hygiene are important in caring for patients with CRF and poor sleep.⁴⁴ Taking a warm bath and/or drinking a glass of milk before bedtime, avoiding caffeinated drinks, and avoiding frequent napping in the day might help. Some patients may require medications such as benzodiazepines or non-benzodiazepine hypnotics (eg, zolpidem) to promote sleep.⁴⁵ Melatonin agonists are approved for insomnia in the United States, but not in Europe.⁴⁶

Malnutrition. Patients with advanced-stage cancer and with cancers affecting the gastrointestinal tract frequently develop mechanical bowel obstructions, especially at the end of their life, which cause malnutrition. Chemotherapy-related nausea and vomiting may also cause poor oral intake and malnutrition, causing fatigue from muscle weakness. Dehydration and electrolyte imbalances frequently occur as a result of poor oral intake, which might worsen fatigue. In our experience, modifying dietary intake with appropriate caloric exchanges with the help of a nutrition expert has lessened fatigue in some patients. However, terminally ill patients are advised to eat based on their comfort.

Medical comorbidities. Congestive heart failure from anthracycline chemotherapy, hypothyroidism after radiation therapy for head and neck cancers, renal failure, or hepatic failure from chemotherapy may indirectly lead to fatigue. Chemotherapy, opioids, and steroids may cause hypogonadism, which can contribute to fatigue in men.⁴⁷

Assessment of Concurrent Symptoms

Depression is common in cancer patients and coexists with pain, insomnia, fatigue, and anxiety as a symptom cluster.⁴⁸ A symptom cluster is defined as 2 or more concurrent and interrelated symptoms occurring together; treating one of these symptoms without addressing other symptoms is not effective.⁴⁹ Therefore, screening for and management of depression, anxiety, and insomnia play an important role in the management of CRF.

Physical symptoms due to the tumor or to therapy— such as pain, dyspnea, nausea, and decreased physical activity—may also contribute to fatigue both directly and indirectly. Patients with lung cancer may have hypoxemia, which can contribute to dyspnea with activity and a perception of fatigue. Optimal management of pain and other physical symptoms in patients with cancer may significantly alleviate fatigue.⁵⁰

MANAGEMENT

Management of CRF is individualized based on the patient’s clinical status: active cancer treatment, survivor, or end of life. Education and counselling of patients and their caregivers play an important role in CRF. NCCN guidelines recommend focusing on pain control, distress management, energy conservation, physical activity, nutrition, and sleep hygiene.

Nonpharmacologic Interventions

Energy conservation. Energy conservation strategies, in which patients are advised to set priorities and realistic expectations, are highly recommended. Some energy-conserving strategies are to pace oneself, delegate and schedule activities at times of peak energy, postpone nonessential activities, attend to 1 activity at a time, structure daily routines, and maintain a diary to identify their peak energy period and structure activities around that time.^51,52 When patients approach the end of life, increasing fatigue may limit their activity level, and they may depend on caregivers for assistance with activities of daily living, monitoring treatment-related adverse effects, and taking medications, especially elderly patients.⁵³