What is the best treatment after thyroid cancer?

It depends: It depends on the type of thyroid cancer and the treatment you've had so far. Usually, you need treatment with thyroid hormone to suppress any remaining gland and replace missing thyroid hormone. You will need to be followed with blood tests. Occasionally, you may require other therapy. Many types of thyroid cancer just need surgery.

Depends entirely: upon the type of thyroid cancer and extent of previous treatment. Assuming that it is papillary cancer, the most common type, and that you already had surgery and radiation, the most common form of treatment, you need to be on thyroid replacement meds. You should also get an imaging study to make sure that all of the cancer has been removed. Talk to your doctor about proper follow up.