There are many causes of wasting and weakness, including improper diet, lack of sleep, etc. It can also be a concomitant symptom of many diseases, and is not a unique sign of cancer. If the patient loses 10 pounds or even 20 pounds in a short period of time, and is accompanied by fever, cough, bloody sputum, night sweats and other symptoms, you should be highly alert to the possibility of tuberculosis and malignant tumors, and go to the hospital for examination, clear diagnosis and symptomatic treatment.