It is wrong to say that cancer cannot be cured. Many cancers can be cured and the key to cure cancer lies in early detection, early diagnosis and early treatment. Some early cancers, especially in situ cancers that have not yet invaded the mucosal layer, can be completely cured by surgical excision alone as long as they can be detected and diagnosed through pathological examination in time. Even if the cancer cells break through the submucosal layer and even local lymph node metastasis occurs, regular radiotherapy or chemotherapy after surgery can enable more than 50% of patients to survive for a long time without recurrence. It is only when the cancer reaches the advanced stage and the cancer cells spread throughout the body that most of the patients cannot be cured at this time. At this time, cancer cells are like seeds that have taken root everywhere in the body and are difficult to be completely removed by current treatments. The only thing that can be done is to control the further spread of cancer cells and prolong the patient’s life as much as possible.