Cancer-Related Fatigue: Approach to Assessment and Management
2017 September;12(5):10-12
References
OTHER HYPOTHESES
Several other hypotheses for CRF pathogenesis have been proposed. Activation of latent viruses such as Epstein-Barr virus, lack of social support,22 genetic alterations in the immune pathway,23 epigenetic changes,24 accumulation of neurotoxic metabolites and depletion of serotonin by indoleamine 2,3-dioxygenase pathway activation,25 elevated vascular endothelial growth factor levels,26 and hypoxia-related organ dysfunction due to anemia or hemoglobin dysfunction13 all have been postulated to cause CRF.
EVALUATION AND TREATMENT
Fours steps are involved in the evaluation and treatment of CRF (Figure).
Patients are screened for fatigue as the first step, and those who have fatigue undergo a primary evaluation to assess for potential precipitating causes. The third step is implementation of pharmacologic and nonpharmacologic interventions aimed at alleviating or mitigating fatigue. The fourth step involves reevaluating patients periodically to recognize and manage changes in fatigue levels. A multidisciplinary approach involving nursing, physical therapy, social work, and nutrition is critical in managing fatigue in these patients. Education and counselling of patients and involvement of the family are essential for effective management as well.
SCREENING
Because patients and health care professionals may be unaware of the treatment options available for CRF, patients may not report fatigue levels to their clinicians, and clinicians may not understand the impact of fatigue on their patients’ quality of life. This leads to under-recognition of the problem. The NCCN recommends screening every cancer patient and post-treatment survivor for fatigue.2 Patients should be screened at their first visit and then at periodic intervals during and after cancer treatment.
Many scales are available to screen patients for CRF in clinical practice and clinical trials.27 A single item that asks patients to rate their fatigue on a scale from 0 to 10—in which 0 indicates no fatigue, 1 to 3 indicates mild fatigue, 4 to 6 indicates moderate fatigue, 7 to 9 indicates severe fatigue, and 10 indicates the worst fatigue imaginable—is commonly used to screen for CRF.2 This scale was adapted from the MD Anderson Symptom Inventory scale and is based on a large nationwide study of cancer patients and survivors.28 The statistically derived cutoff points in this study are consistent with other scales such as the Brief Fatigue Inventory (BFI) and support the cutoff points (4–6 for moderate and ≥ 7 for severe fatigue) used in various fatigue management guidelines. Furthermore, studies of fatigue in cancer patients have revealed a marked decrease in physical function at levels of 7 or higher, suggesting 7 as an optimal cutoff to identify severe fatigue.29,30 The Visual Analog Scale is another simple-to-use tool that helps in understanding variations in fatigue throughout the course of the day.31 The 9-item BFI is often used in clinical trials.29 It measures the severity of fatigue over the previous 24 hours and has been validated in patients who do not speak English.32
CRF affects not only the somatic domain, but also the cognitive, behavioral, and affective domains; therefore, multidimensional scales have been developed for screening. One such tool is the Multidimensional Fatigue Inventory, which assesses 5 dimensions of fatigue—general fatigue, physical fatigue, reduced motivation, reduced activity, and mental fatigue—and compares the patient’s results with those of individuals without cancer.33,34 The Functional Assessment of Cancer Therapy for Fatigue (FACT-F) is a 13-item questionnaire that has been used to measure CRF in clinical trials as well as in patients receiving various treatments.35
Although many scales are available, the validity of self-reporting on simple fatigue-rating scales is equal to or better than most complex, lengthy scales.36 Therefore, unidimensional tools such as the numeric rating scale of 0–10 are commonly used in clinical practice. Mild fatigue (0–3) requires periodic reevaluation, and moderate and severe fatigue need further evaluation and management.37
PRIMARY EVALUATION
This phase involves a focused history and physical examination and assessment of concurrent symptoms and contributing factors.
History and Physical Examination
A detailed history of the patient’s malignancy and type of previous and current treatment may help reveal the cause of fatigue. New-onset fatigue or increase in fatigue may be related to the progression of disease in patients with active malignancy or recurrence of cancer in survivors. These patients may require appropriate testing to assess the underlying disease pattern. A detailed review of systems may help identify some of the contributing factors, which are discussed below. A detailed history regarding medications, including over-the-counter drugs, complementary agents, and past and prior cancer therapies, is helpful as medications can contribute to fatigue. For example, opioids may cause drowsiness and fatigue, which could be improved by dose adjustments. A focused history of fatigue should be obtained in all patients with moderate to severe CRF, which includes the onset, pattern, duration, associated or alleviating factors, and interference with functioning, including activities of daily living.37 Physical examination should focus on identifying signs of organ dysfunction and features of substance or alcohol abuse, which may cause poor sleep and fatigue.
