Whether radiotherapy can be used for recurrence of esophageal cancer after radiotherapy is more complicated, for example, general radiotherapy can only be performed once in a lifetime for a site. Because of the toxic involvement of radiotherapy, it is not the case that all functions can be restored after a period of time without radiotherapy recently. The toxicity of more organs accumulates, and it is rare to repeat a site twice. Once the esophageal cancer recurs after radiotherapy, radiotherapy can also be chosen, but the efficacy of radiotherapy may be poorer than the first radiotherapy. In addition, it is generally recommended to start radiotherapy after two years. After two years, patients need to be evaluated comprehensively to see their physical condition, whether there is any possibility of fistula and to exclude possible complications before starting to decide whether to start radiotherapy. However, radiotherapy is not an option for many patients, and patients need to weigh the pros and cons. Because radiotherapy may have limited effectiveness but can have more serious side effects, a comprehensive evaluation by the radiologist is needed to assess whether the patient can undergo radiotherapy. Another rare type of radiotherapy is internal irradiation. In some cases, external irradiation cannot be performed if the esophageal cancer recurs again soon after treatment. There is a method called internal irradiation, in which the irradiation source is introduced directly into the esophagus through a catheter, after which the radiation source stays at the tumor for a period of time in order to irradiate the tumor. The advantage of its treatment is that it has less impact on the surrounding organs, so this method can be chosen, but it can only achieve the purpose of palliative treatment.