Final answer:
The least aggressive thyroid cancer is papillary thyroid cancer. It grows slowly and rarely spreads to other parts of the body. Treatment typically involves surgery and radioactive iodine therapy.
Step-by-step explanation:
The least aggressive thyroid cancer is papillary thyroid cancer. It is the most common type of thyroid cancer and generally has a good prognosis. It grows slowly and rarely spreads to other parts of the body. The treatment for papillary thyroid cancer often involves surgery to remove the thyroid gland, followed by radioactive iodine therapy to destroy any remaining thyroid cells.