Is metastatic thyroid cancer of the lungs treatable?

Difficult. It is treatable, but the cure rates are difficult once thyroid cancer has spread to the lungs. If this is not a hypothetical question for you or someone you know, there is limited data that a tyrosine kinase inhibitor may be helpful; it would at least be worth inquiring with your physician for their thoughts on the subject.
Thyroid cancer. Treatment of thyroid cancer metastases in the lung depends on if it takes up radioactive iodine. If the tumors are small in the lung and take up radioactive iodine, then the treatment is a large dose of radioactive iodine. If the tumors do not take up radioactive iodine, the best course is to "wait and watch". If the tumors continue to growth, then there are new drugs called tyrosine kinase inh.