have not yet been reported. The rst technique for chemoembolization of medullary thyroid cancer is with drug-eluting beads bound to doxorubicin (DEB-DOX) in order to prime the eld for radiotherapy. Ideally, this would be minimally embolic as the mechanism of tumor death by radiotherapy is oxygen free radical formation, an important distinction from the embolic endpoint in medullary thyroid carcinoma where liver metastases are embolized with DEB-DOX to stasis to obtain best results [49]. DEB-DOX would carry the benet of minimizing non-target dose in patients with cardiac comorbidities for the cardiotoxic doxorubicin. The second technique that has not yet been reported is the locoregional delivery of antibody-bound radio­immunotherapeutics such as yttrium-90-anti-CEA [8]. Since medullary thyroid car­cinomas can express carcinoembryonic antigen (CEA) on their surface, the yttrium-90-anti-CEA therapy has shown to be effective. However, the systemic infusion of radiolabeled antibodies is known to cause dose-limiting hematologic toxicity, usually requiring pre-treatment harvest of peripheral blood stem cells. Endovascular drug delivery, possibly with a ow-limiting catheter to enhance rst­pass extraction in the tumor, may one day substantially limit the number of patients in which “myeloablative” protocols of radiolabeled antibody therapy are needed to obtain adequate tumor response such as in patients with locoregional inoperable disease. Additionally, a common pitfall for radioimmunotherapy and nanoparticle­directed therapy is extraction in the reticuloendothelial system, namely, the spleen [50], whereby the aforementioned injection techniques may allow a smaller dose of the therapeutic to be injected directly to the target, in a repeatable fashion if desired. Gene therapies targeted with viral vectors [51] have been developed for medullary thyroid cancer and can also be delivered in the same fashion, although this has not yet been reported.

by causing redifferentiation in six of ten patients, with two of six having a partial response [58]. Dabrafenib has a neutral charge and therefore may not be directly chemically bound to existing drug elution bead platforms; however very recently, an immobilizable analogue i-Dabrafenib has been created [59] for adhesion to sepha­rose beads. Forthcoming trials may study DEB-DAB microenvironmental priming for radio-sensitization or chemo-sensitization of locally advanced PTC. It would be important to mix these with gadolinium so as not to saturate the target thyroid tissue with iodine from iodinated contrast. This would competitively inhibit the binding of radioactive iodine treatment for weeks to follow, delaying the patient’s therapy [60].