Everyone who has nail cancer knows that surgery is required, but not everyone (including some surgeons) knows that radioactive iodine treatment is required after surgery. The recurrence rate of nail cancer treated by surgery alone is about 33%, while the recurrence rate of surgery followed by radioactive iodine treatment is less than 3%. Why do many patients (including some surgeons) neglect post-surgical radioactive iodine treatment? The main reason is that 80% of nail cancer is highly differentiated cancer, and the prognosis of highly differentiated cancer is better, even if the recurrence after surgery is 5-10 years later, since cancer can live for 10 years, patients and physicians feel that the treatment effect is very good. In fact, many patients can survive for life if they are treated with radioactive iodine after surgery. Another important reason for postoperative radioactive iodine treatment is that even a highly skilled surgeon cannot cut out the entire thyroid gland, so some hidden lesions may remain and become the seeds of recurrence. In addition, some metastases of nail cancer are relatively hidden and cannot be detected even by CT, which also provides the possibility of recurrence. Therefore, the necessity of postoperative radioiodine therapy can be imagined. Some patients think that once the metastasis and recurrence of nail cancer are detected, it is the end. In fact, radioiodine treatment for metastasis and recurrence is also very effective. Like a missile, high dose radioactive iodine can actively find metastasis and recurrence of nail cancer and remove it in a targeted manner. Therefore, we should actively adopt effective methods for the treatment of nail cancer and should not be blindly optimistic or pessimistic. Surgical operation plus radioactive iodine is the best combination to treat nail cancer.