ABSTRACT
<p><b>OBJECTIVE</b>To evaluate the effect of 90Y-DOTATOC and 131I-MIBG in treatment of metastatic medullary thyroid carcinoma (MTC).</p><p><b>METHODS</b>Twelve histologically confirmed patients with metastatic MTC were included. All patients underwent both 111In-DTPA-octreotide imaging and 131I/ 123I-meta-iodobenzylguanidine (MIBG) imaging. According to the results of the combined imaging, positive patients were selected to be treated with 90Y-DOTA-D-Phe1-Tyr3-octreotide (90Y-DOTATOC) or 131I-MIBG, respectively. The therapeutic procedures of targeted internal radiation were performed with 3.33 GBq 90Y-DOTATOC at 6-week intervals, or 11.1 GBq 131I-MIBG with a minimum interval of three months.</p><p><b>RESULTS</b>The imaging procedure was positive in all 12 patients: 111In-DTPA-octreotide imaging in eight patients, 131I/ 123I-MIBG imaging in six patients. According to the results of combined imaging, we identified four patients to be treated with 90Y-DOTATOC, and five patients with 131 I-MIBG. After three to five sessions of treatment, three patients with partial remission and six with stable disease were observed. The effective rate was 3/9 (33.3%) and the overall tumor response rate was 9/9 (100%). No relevant toxicity was observed.</p><p><b>CONCLUSION</b>The combined imaging technique can be used to identify patients for effective radionuclide treatment. The treatment with 90Y-DOTATOC or 131I-MIBG is well tolerated and may improve the fate of patients with metastatic MTC.</p>