It depends on extent of the cancer. Usually it is curable with radioactive iodine or surgery. If already spread/metastatic the curative rate is less

That depends on the type a cancer & at what stage it has progressed. Some types of thyroid cancer do not spread & can be removed by surgery & cured. Some are more severe & can spread throughout the body. If she has this form of cancer & it has not spread yet, it can probably be cured by removal of the thyroid perhaps followed by some chemotherapy or radioactive Iodine. If it has spread more aggressive chemo &/or radioactive iodine will be needed and may or may not cure it. In any event, thyroid cancer is less life threatening than many other forms of cancer & the prognosis is good especially if caught early.