Although lung cancer is a killer of human health, the reality is that many lung cancer patients are not diagnosed until the middle or late stage, which makes treatment quite difficult. Early symptoms of lung cancer may not be so obvious that they are ignored by many patients. Take a look at what are the symptoms of lung cancer in the middle and late stages. 1. Chest pain Chest pain is caused by the invasion of tumor cells into some organs in the chest cavity. The chest cavity is a very complicated space, three-quarters of the lung surface is surrounded by the chest wall, which is composed of a thin layer of lining (wall pleura), fat, muscle, ribs and skin in different proportions. Tumor invasion of any of these parts will cause pain. Therefore, most of the lung cancer patients with intra-thoracic regional dissemination have symptoms of chest pain. 2.Heartiness Lung cancer patients in the middle and late stages will usually experience hoarseness. This is because the recurrent laryngeal nerve, which controls the left side of the articulation function, goes down from the neck to the chest, and returns up to the larynx around the large blood vessels of the heart, thus innervating the left side of the articulation organ. Therefore, if the tumor invades the left side of mediastinum, the laryngeal nerve will be compressed and hoarseness will be produced, but there is no pharyngeal pain and other symptoms of upper respiratory infection. 3. Pleural effusion and shortness of breath Shortness of breath is due to the fact that the tumor in the lung of patients with middle and late stage lung cancer has invaded most of the lung tissue. The normal tissue fluid produced by the lung and heart muscle is returned by the lymph nodes in the middle of the chest. If these lymph nodes are blocked by the tumor, this tissue fluid will accumulate in the pericardium to form a pericardial effusion or in the thorax to form a pleural effusion. Both of the above conditions can lead to shortness of breath. 4.Face and neck edema There is superior vena cava in the right side of mediastinum, which transmits venous blood from upper limbs and head and neck back to heart. If the tumor invades the right side of the mediastinum and compresses the superior vena cava, the jugular vein will initially become angry due to poor return flow, and finally it will lead to facial and neck edema, which needs to be diagnosed and treated in time. The above are the symptoms of middle and late stage lung cancer, which are quite obvious. It is only that many patients do not have proper health awareness, or they feel abnormalities in their body but do not consider it a serious situation, which results in late diagnosis and treatment of lung cancer. This shows how important a good health awareness is.