Compared with normal people, cancer patients have a more severe degree of correlated weakness, which is not only easily depressed, but also cannot be relieved by rest, which seriously affects the quality of life. What are the symptoms of cancer-related fatigue? In one study, cancer patients perceived fatigue to be more disruptive to their quality of life than nausea, depression and pain combined. The International Classification of Diseases criteria describe cancer-related fatigue as symptoms of non-specific weakness, weakness, generalized decline, drowsiness or insomnia, fatigue, lack of energy, feelings of sadness, irritability, feeling of heaviness in the limbs, slow movement, weakness, and anxiety. According to the National Comprehensive Cancer Network guidelines, cancer malaise is a painful, persistent, subjective feeling of exhaustion. It is disproportionate to the body’s activity level, is associated with cancer or cancer treatment, and is often accompanied by functional impairment. Why is there such a large percentage of malaise? Can this malaise be relieved? There are about 5 aspects that are thought to cause the weakness, and to relieve or overcome this weakness, the individual’s emotion is very important to maintain an optimistic mood. Why does cancer weakness occur? 1.Direct influence of tumor Tumor changes the metabolism of the body through various ways, and the body cannot absorb nutrients from outside. For example, esophageal cancer, stomach cancer, colon cancer, etc. will affect the food intake and nutrient absorption, resulting in the lack of calories and electrolytes required by the body, which will cause weakness; bone tumors or tumors with bone metastases often cause typical tumor emergencies such as hypercalcemia, characterized by fatigue, regurgitation, thirst, frequent urination, etc.; lymphoma and blood tumors often cause anemia, which is also an important cause of weakness. Tumor cells also take nutrients from the body’s inherent fat and protein. If the body is in a state of malnutrition for a long time, fatigue will be aggravated. Advanced tumor patients will also deteriorate due to severe malnutrition, leading to weakness. 2.Tumor treatment ①More than 65% of chemotherapy patients, 82%~96% of radiotherapy patients, and more than 70% of patients receiving interferon therapy will experience cancer fatigue. ②Radiotherapy makes toxic cell degradation products accumulate, increases energy consumption, causes liver cell damage and thus oxidative changes, etc., all of which can cause fatigue. ③ Chemotherapy can cause nausea and vomiting and loss of appetite, which reduce the body’s energy intake; poor bowel movements, pain and insomnia increase the body’s energy consumption, and the body’s demand for energy exceeds the energy supply, all of which can lead to fatigue. ④The bone marrow suppression caused after chemotherapy can also lead to fatigue, especially most obvious around 7~14 days after chemotherapy. ⑤ Adjuvant drugs for pain relief have a sedative-hypnotic effect while relieving pain, which can be mistaken for fatigue by patients. ⑥Breast cancer patients receiving endocrine therapy lose calcium in their bones after the estrogen level in their body decreases, and the most obvious symptom is weakness in walking. In addition, the injury of surgical treatment itself, postoperative pain, subsequent repair reactions, subsequent effects of anesthesia, health disorders caused by bed rest, and blood loss anemia may all affect the patient’s physical ability. 3.Lactic acid accumulation Tumor tissues mainly rely on carbohydrates for energy, the utilization of glucose rises and lactic acid production increases. The lactic acid cycle in normal people accounts for 20% of glucose conversion, while the lactic acid cycle in tumor patients increases to 50%, and the accumulation of lactic acid easily leads to weakness. 4. Chronic comorbidity Pain is a common symptom of cancer patients, which easily leads to sleep disorder. Tumor and its treatment induce changes in hormonal homeostasis of immune system, activate pro-inflammatory cytokine network and produce chronic inflammatory response, which leads to symptoms of fatigue. 5. Psychological factors The diagnosis, treatment, dysfunction, economic burden and change of self-image of tumor will cause patients to have anxiety and depression. These psychosocial factors change the stability of the body’s internal environment by affecting the body’s autonomic nervous system, endocrine system, neurotransmitters and immune system, and destroy the body’s defense system, which eventually leads to weakness. What should be taken to overcome cancer weakness? 1.Actively recognizing the related causes of cancer weakness is the primary measure of treatment. When the following symptoms appear, such as cancer pain, depression, sleep disorder, anemia, malnutrition, decreased exercise level and other comorbidities, rehabilitation therapy, cognitive-behavioral therapy, sleep intervention therapy, nutritional support therapy, social intervention, etc., and drug therapy if necessary. 2.To overcome cancer weakness, patients’ emotion is very important. Patients should maintain an optimistic mood, dare to admit the real existence of cancerous weakness and recognize its unique manifestations, and tell the attending physician about the fatigue in time so that he or she can make appropriate treatment to relieve the symptoms of weakness and reduce the pain to the greatest extent. 3. Patients should also pay attention to nutritional supplementation. During the surgical treatment, multi-sugar and protein-rich food should be the mainstay, and fat helps prevent the fluctuation of the body’s energy level from being too high or too low. It should be noted that the original recipe and routine should not be easily changed to avoid excessive hunger or overeating. 4. Ensure that you get at least 8 hours of sleep every night. But too much rest will make people feel more tired. Patients had better record the sleep time and the next day’s feeling, in order to know the most can maintain a good state of rest time. 5, moderate exercise activities and recreational activities are also important for patients. Some studies have shown that moderate exercise can improve cancer fatigue. It is difficult to say exactly which exercise program is the best and how long is the most appropriate. Patients are advised to choose the exercise they like more, and the duration and intensity of the activity should be as long as they feel comfortable. It is important to note that one should not over-exercise, and only one activity should be chosen at a time to ensure the energy balance between rest and activity.