Most people will not experience voice changes after esophageal cancer surgery; if the recurrent laryngeal nerve is damaged during the surgery, patients may experience hoarseness or weak voice and speech weakness. The causes of recurrent laryngeal nerve injury include anatomical basis, severity of disease and lymph node metastasis. 1. Anatomical basis: the higher the location of esophageal cancer, the closer it is to the recurrent laryngeal nerve, the higher the chance of recurrent laryngeal nerve injury during operation. 2. Disease severity: the deeper the infiltration of esophageal cancer, the more serious the invasion, the wider the scope of tumor separation during operation, the higher the chance of injury to the recurrent laryngeal nerve. 3. Lymph node metastasis: lymph nodes under the arch of the aorta, lymph nodes at the esophageal groove and lymph nodes in the neck are closely related to the recurrent laryngeal nerve and are prone to metastasis of esophageal cancer, so the recurrent laryngeal nerve may be directly injured when the operation is performed to clear these lymph nodes. Patients should fully understand the situation before surgery and carry out standardized treatment under the guidance of doctors to reduce the occurrence of adverse phenomena.