[Management of patients with thyroid tumors; global trends, current status in Japan and clinical problems and questions].

The incidence of thyroid cancer clinically detected is increasing, mainly due to the technical progress in thyroid sonography. There are many problems and questions regarding the management of patients with thyroid tumors, including how to distinct thyroid follicular cancer from adenoma (no definite method is available except for the histological examination of the tissue specimen at surgery), how to treat patients with unproved thyroid tumor (thyroidectomy or observation ?), how to define "poorly differentiated thyroid cancer" (different definition between WHO and Japan) and how to treat patients with differentiated thyroid cancer (total thyroidectomy or subtotal thyroidectomy, with or without prophylactic neck dissection, with or without postoperative remnant ablation by radioactive iodine, with or without postoperative TSH suppression by thyroid hormone, thyroidectomy or observation for micro-carcinoma). Several guidelines for management of thyroid tumors have recently been published from western thyroid associations. Their basic policy how to manage differentiated thyroid cancer is considerably different from, at least, the traditional treatment in Japan. An evidence-based guideline should be published soon in