The difference between intermediate and advanced stages of thyroid cancer mainly lies in the size of tumor, location of metastasis and symptoms. 1. Tumor size: the tumor size of intermediate thyroid cancer does not infiltrate the anterior cervical fascia or encircle the carotid artery or mediastinal blood vessels, etc., while the tumor of advanced thyroid cancer infiltrates the anterior cervical fascia or encircles the carotid artery or mediastinal blood vessels. 2. Location of metastasis: intermediate-stage thyroid cancer is accompanied by lymph node metastasis, such as pre-tracheal lymph node and paratracheal lymph node metastasis; while advanced thyroid cancer not only has lymph node metastasis, but also has metastasis to distant organs, such as bone and lung metastasis. 3. Symptoms: in the middle stage of thyroid cancer, symptoms may include neck mass, enlarged lymph nodes in the neck, hoarseness due to tumor compression, etc. In the late stage, systemic symptoms such as fever, pleural effusion, hemoptysis, and bone fracture after metastasis are the main symptoms. If you suffer from thyroid cancer, you should seek medical treatment as early as possible.