Cancer and deliberate hypothyroidism, anesthesia, and myxedema coma: the curse of oncologic outcomes based on hypothyroidism

[...]although the primary effect of TKIs is to decrease thyroid production of the prohormone thyroxine (T4), the hypothyroidism produced by TKIs is unique in that it is also caused by the reduced intracellular conversion of T4 to its active form, triiodothyronine (T3)1 [3,6,7]. [...]the classical description of the hypothalamic-pituitary-thyroid (HPT) feedback loop that we all learned in medical school needs to be updated if we are to understand why the new antineoplastic agents cause hypothyroidism and how certain physiologic stresses can trigger myxedema coma [10,11].