[Surgical Treatment of Thyroid Cancer]

The strategy for surgical treatment of thyroid cancer differs depending on the histopathological type. In papillary thyroid cancer, which accounts for most cases of thyroid cancer, total thyroidectomy is recommended in high-risk cases with tumors of more than 5 cm or with N1, EX2, or M1 tumors in Japan. On the other hand, ipsilateral lobectomy is performed for low-risk cases with T1N0M0. Our department has also added a treatment policy for the prognostic factor, age. Prophylactic lymph node dissection is performed in the central neck region but is not recommended in the lateral neck region. In follicular thyroid cancer, total thyroidectomy is recommended for widely invasive cancer, and hemithyroidectomy or ipsilateral lobectomy is performed for minimally invasive cancer. When widely invasive cancer is diagnosed after lobectomy, completion thyroidectomy is recommended. Whether minimally invasive follicular cancer with vascular invasion requires completion thyroidectomy is controversial. I also handle medullary thyroid cancer, poorly differentiated thyroid cancer, undifferentiated thyroid cancer, and thyroid malignant lymphoma with a different policy. It is important to balance a surgical treatment strategy with a molecular targeted therapy and radioactive iodine treatment.