Hoarseness is an important manifestation of lung cancer. Hoarseness can occur after laryngitis, cold and acute bronchitis, thyroid surgery, pharyngeal surgery, improper vocalization, excessive speech or even heavy smoking and drinking. However, this type of hoarseness can usually be treated symptomatically or cured spontaneously with rest. Hoarseness caused by lung cancer, thyroid cancer and laryngeal cancer is completely different from the above type of hoarseness, especially lung cancer. Hoarseness caused by lung cancer often occurs suddenly, progresses rapidly, or even loses its voice completely, and most patients are accompanied by chest pain, etc., which has no effect even after rest and anti-inflammatory symptomatic treatment for more than two weeks. Does hoarseness mean advanced lung cancer? After lung cancer, when the tumor compresses or invades the recurrent laryngeal nerve, symptoms such as hoarseness will appear. Especially, the left laryngeal recurrent nerve starts from between the aortic arch and the left main bronchus and travels a longer distance in the chest than the right laryngeal recurrent nerve. Therefore, the left recurrent laryngeal nerve is more susceptible to thoracic lesions than the right. Generally speaking, when the laryngeal recurrent nerve is invaded and hoarseness appears, it can be considered that lung cancer has developed to an advanced stage.