A large toxic retrosternal goiter is best treated by-

Retrosternal goitre is most commonly defined as one that either descends below the thoracic inlet, or has more than 50% of its volume below this level. Surgery is the only effective treatment for retrosternal goitres. In most cases, suppressive therapy with thyroxine is ineffective in reducing the size of multinodular goitres ; radio-iodine therapy is both generally ineffective in large goitres and may induce acute inflammation and swelling of the gland with the potential for airway obstruction. Ref - <a href="