Chest X-ray is mainly to check lesions in the lungs. Although there is no direct connection between liver cancer and lung, patients with liver cancer routinely undergo chest X-ray. One of the reasons for liver cancer patients to have chest X-ray is to detect tumors in the septum adjacent to the liver. When liver cancer grows in the liver area under the septum muscle, it will lift up the septum muscle, and chest X-ray can detect a limited bulge of the right septum muscle, which is an important sign for diagnosing liver cancer. Another reason is that liver cancer is prone to lung metastasis. For example, there were patients with liver cancer who first found metastatic cancer in the lung during physical examination, and then found liver cancer only when they examined the liver further.