Cancer-related fatigue is a symptom of fatigue that is experienced by nearly all cancer patients.
Among patients receiving cancer treatment other than surgery, it is essentially universal. Fatigue is a normal and expected side effect of most forms of chemotherapy, radiation therapy, and biotherapy. On average, cancer-related fatigue is "more severe, more distressing, and less likely to be relieved by rest" than fatigue experienced by healthy people. It can range from mild to severe, and may be either temporary or a long-term effect.
Fatigue may be a symptom of the cancer, or it may be the result of treatments for the cancer.
Pathophysiology The pathophysiology of cancer-related fatigue is poorly understood. It may be caused by the cancer or the effects it has on the body, by the body's response to the cancer, or by the cancer treatments.
Fatigue is a common symptom of cancer. One meta-analysis estimated that around 43% of individuals with cancer report experiencing fatigue. The study also highlighted that fatigue levels can differ depending on factors like the type of cancer, the stage of treatment, and gender. Notably, women were found to experience more severe fatigue than men.
Some fatigue is caused by cancer treatments. This may show a characteristic pattern. Chemotherapy is a form of cancer treatment that can result in cancer-related fatigue, either as a direct consequence or as a secondary effect. Disturbed sleep during chemotherapy has also been associated with CRF in breast cancer survivors. Chemotherapy can damage the sarcoplasmic reticulum and/or mitochondria, potentially leading to a disrupted energy metabolism and an increased risk of peripheral fatigue. For example, people on many chemotherapy regimens often feel more fatigue in the week after treatments, and less fatigue as they recover from that round of medications. People receiving radiation therapy, by contrast, often find their fatigue steadily increases until the end of treatment.
Radiotherapy can result in CRF. For example, studies have shown that radiotherapy increased cancer related fatigue in some cancers. Fatigue is a prevalent side effect of radiation therapy and can significantly limit patients' daily activities. Typically, fatigue intensifies during the initial stages of treatment, reaches a plateau around the midpoint, and remains relatively stable until therapy concludes. Although many patients experience gradual improvement after treatment ends, others report fatigue that persists for months or even years. In some cases, energy levels may not fully return to pre-treatment baselines .
Treatment for cancer such as surgery can result in CRF, either directly or as a secondary effect. However, when surgery is combined with other cancer therapies such as chemotherapy or radiation fatigue can be more pronounced and prolonged.
A systematic review and meta-analysis found that approximately 42% of working cancer survivors report experiencing cancer-related fatigue. The analysis also identified emotional distress as a possible contributing factor to ongoing fatigue symptoms. These findings suggest that both physical and psychological factors may influence fatigue in working survivors, indicating the potential value of supportive workplace strategies
Proposed mechanisms by which cancer can cause fatigue include an increase in pro-inflammatory cytokines, dysregulation of the hypothalamic-pituitary-adrenal axis, disruption of circadian rhythms, muscle loss and cancer wasting, and genetic problems. Additionally, some forms of cancer may cause fatigue through more direct mechanisms, such as a leukemia that causes anemia by preventing the bone marrow from producing blood cells efficiently. A relationship between Interleukin 6 and fatigue has been observed in studies, albeit inconsistently. Increased markers of sympathetic nervous system activity are also associated with cancer related fatigue.
Screening The National Comprehensive Cancer Network recommends that every cancer patient be systematically screened for fatigue at the first visit with an oncologist, throughout treatment, and afterwards. Screening typically involves a simple question, like "On a scale of one to ten, how tired have you felt during the last week?"
More detailed information may be collected in a symptom journal.
Diagnosis Some causes of cancer-related fatigue are treatable, and evaluation is directed towards identifying these treatable causes. Treatable causes of cancer-related fatigue include: anemia, pain, emotional distress, sleep disturbances, nutritional disturbances, decreased physical fitness and activity, side effects from medications (e.g., sedatives), abuse of alcohol or other substances. Additionally, other medical conditions, such as infections, heart disease, or endocrine dysfunction (e.g., hot flashes), can cause fatigue, and may also need treatment.
Definition The National Comprehensive Cancer Network defines cancer-related fatigue as "a distressing persistent, subjective sense of physical, emotional and/or cognitive tiredness or exhaustion related to cancer or cancer treatment that is not proportional to recent activity and interferes with usual functioning".
Cancer-related fatigue is a chronic fatigue (persistent fatigue not relieved by rest), but it is not related to chronic fatigue syndrome. Cancer-related fatigue occurs in a significant proportion of cancer survivors, both during and after cancer treatment. A review of current evidence indicates that exercise is the most effective way of ameliorating cancer-related fatigue.
Prostate cancer
Cancer related fatigue is common in patients undergoing treatment for prostate cancer. A systematic review of the prevalence of cancer-related fatigue in men with prostate cancer was performed. The analysis indicated that fatigue is a common symptom, occurring in about 40% of men with prostate cancer especially among those using hormone therapy.
Breast cancer Cancer-related fatigue is a prevalent and significant symptom among breast cancer patients, often lasting for years after treatment. An empirical study regarding cancer-related fatigue in breast cancer patients identified different groups of patients based on their fatigue levels, with nearly half (47.5%) falling into an "exhausted" group, characterized by high fatigue severity and interference in daily activities, along with elevated stress, anxiety, depression, and sleep disturbance, significantly impacting quality of life.
Management Treatment depends on the patient's overall situation. A patient who is in active treatment may have different priorities than a person who has completed treatment, or who is at the end of life.
Some management strategies may help all patients and could be supported by the work of an Occupational Therapist. These include scheduling high-priority tasks during the patient's best time of day, using labor-saving devices, delegating tasks to caregivers, and avoiding unimportant activities, so that the patient will have more energy available for other activities.
Patients who are not at the end of life may benefit from physical exercise or physical therapy. Engaging in physical activity may reduce fatigue.Jose Stephy, Diwan Sanjay Kumar. Effect of standardized exercise program on reported fatigue in patients of cancer receiving chemotherapy. Clinical Cancer Investigation Journal 3(5): 373-376 Forms of exercise that have been proven to be most effective are more aerobic exercise such as walking, running, cycling, and swimming. These forms of activity can be done at various levels of intensity and have been proven as an effective way of improving quality of life for cancer patients. A network meta-analysis evaluated the effectiveness of various exercise modalities in alleviating CRF among breast cancer patients. The findings indicated that yoga was the most effective, followed by combined aerobic and resistance exercises. In addition to general exercise and yoga, other mind-body practices such as Qigong have demonstrated potential benefits in managing CRF.
Exercise Cancer-related fatigue is known to interfere with body functions and daily activities. Exercise is thought to improve overall physical functioning by increasing daytime activities, which directly improves cancer-related fatigue. Regular physical exercise offers long-term benefits in reducing the intensity of cancer pain and its disruption of daily life, thereby helping to ease cancer related fatigue. Exercise interventions have shown to significantly improved quality of life and significantly decreased cancer-related fatigue among cancer patients . Aerobic exercise provided considerable improvements in both cancer-related fatigue and quality of life. An intervention less than 12 weeks showed a better effect on both cancer-related fatigue and quality of life and was suggested as most effective . Exercising three times per week was the most effective frequency for improving QoL . Exercise intervention was more successful in improving both CRF and QoL in female cancer patients.
Cancer-related fatigue is often linked to immune dysregulation and inflammatory problems. Exercise interventions can help cancer patients by strengthening the immune system, regulating body balance, and controlling inflammation, which in turn helps to alleviate fatigue . A sedentary lifestyle following a cancer diagnosis can negatively impact QoL and, implicitly, fatigue. Exercise promotes a cost-effective healthy life.
Relaxation During treatment, relaxation is the best choice and should be considered alongside personalized exercise. After treatment, time invested in relaxation sessions is less effective, and health professionals should recommend more physical activity-enhancing interventions. Yoga, aerobic training, resistance training, and combined aerobic-resistance training were beneficial both during and after cancer treatment, though on a lower effect size level than relaxation (during) or yoga (after)
Relaxation specifically had the highest effect size during active cancer treatment. During chemotherapy or radiotherapy, patients often experience high acute stress and physical burden, making stress-reducing interventions like relaxation highly effective. Relaxation may be most critical when patients are acutely struggling with therapy side effects and stress. After treatment, time spent relaxing is less effective, and patients benefit more from physical activity enhancing interventions . Yoga is beneficial in both phases. Its combined effect of physical activity (improving fitness) and mind-body techniques (stress reduction) makes it highly effective.
Role of Social Support Presence of social support for patients is significantly associated with decreased cancer-related fatigue. Often, first-degree relatives such as the parent, sibling, or child of the patient provides social support. Cognitive training coupled with social support has been found to significantly decrease levels of short-term and long-term fatigue.
Yoga