Many people talk about cancer and think that cancer is a terminal disease. However, with the rapid advancement of medical technology, this view is a bit biased. Many cancers that are less malignant and still in their early stages of development can be completely controlled or even cured. Differentiated thyroid cancer, namely papillary thyroid cancer and follicular thyroid cancer, has a good prognosis, with 85% of patients with this type of cancer surviving for more than 10 years. Differentiated thyroid cancer is further divided into two groups: high-risk and low-risk. How to distinguish between high-risk and low-risk is determined by the doctor according to the patient’s specific condition. According to the high- and low-risk staging, patients in the low-risk group have a better prognosis, with about 90% of them surviving for more than 20 years, while about 61% of those in the high-risk group can survive for more than 20 years. Even with metastases from other parts of the body, 25% to 40% still survive for more than 10 years. It is clear that differentiated thyroid cancer is not as scary as people think. Compared to differentiated thyroid cancer, medullary thyroid cancer is a bit scarier and undifferentiated thyroid cancer is the scariest. Medullary thyroid cancer comes from a type of cancer called parathyroid cells (C cells) and accounts for about 5% of thyroid cancers. About 25% of medullary thyroid cancers have a clear family history of inheritance, and 75% are not genetically related. The degree of malignancy varies widely among medullary thyroid cancer cases, some can be stable or even insidious for many years, while others are highly aggressive and have a high mortality rate. In general, 75% of medullary thyroid cancer patients can survive for 10 years. Whether the survival is long or not mainly depends on the age at diagnosis, the size of the cancer, the presence or absence of lymph node metastasis and whether there is distant metastasis. The survival rate of early to mid-stage is 71-100%, while the survival rate of advanced stage is only 21%. Undifferentiated thyroid cancer is a rare and highly malignant tumor, the incidence rate of which does not exceed 3% of thyroid cancer, but the death rate accounts for 85% of thyroid cancer, and it is mostly seen in elderly patients, usually over 65 years old. The prognosis of undifferentiated thyroid cancer is the worst, only very few patients can survive for a long time, and most patients only survive for 4-8 months on average after diagnosis. Since differentiated thyroid cancer accounts for more than 90% of all thyroid cancers, if detected and treated early, it can be almost cured, therefore, about 90% of thyroid cancers are treatable and not terrible. Once you have thyroid cancer, you should neither take it lightly nor overly nervous, but keep a good attitude and cooperate with your doctor for proper treatment.