Depending on the tissue or organ where the cancer begins, there are around 200 types of cancers and these are called primary cancers. Some cancers have a high likelihood of spreading from one tissue to another and this is called metastasis. Secondary or metastatic cancers are those that have spread from primary locations, the location where they have first appeared. Thyroid cancer is the cancer in the thyroid gland, an endocrine organ which produces hormones that control the speed of metabolism.