Lung cancer usually does not lead to foam in urine, and patients mainly show symptoms such as cough, sputum and chest pain. Early symptoms of lung cancer mainly show cough, which may be sputumless or paroxysmal irritating dry cough with little sputum. As the condition of lung cancer aggravates, the tumor will invade neighboring organs and tissues, which often leads to worsening of cough, and the cough will be accompanied by hidden pain or dull pain in chest. When the condition of lung cancer reaches middle or late stage, there may be symptoms such as hemoptysis, dyspnea and hoarseness. However, lung cancer does not lead to changes in urine. If there are bubbles in urine, it may be caused by physiological reasons, such as drinking too little water and concentrating urine, thus forming urine bubbles, or it may be caused by urinary diseases, such as urinary tract infection. If there are bubbles in the urine for a long time, you should go to the hospital in time and cooperate with the doctor to take examination and treatment.