OBJECTIVETo evaluate the effect of 90Y-DOTATOC and 131I-MIBG in treatment of metastatic medullary thyroid carcinoma (MTC).

METHODSTwelve 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.

RESULTSThe 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.

CONCLUSIONThe 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.

3-Iodobenzylguanidine ; therapeutic use ; Adult ; Aged ; Antineoplastic Agents ; therapeutic use ; Carcinoma, Medullary ; metabolism ; radiotherapy ; secondary ; Female ; Follow-Up Studies ; Humans ; Indium Radioisotopes ; Male ; Middle Aged ; Octreotide ; analogs & derivatives ; therapeutic use ; Pentetic Acid ; analogs & derivatives ; Positron-Emission Tomography ; Remission Induction ; Thyroid Gland ; diagnostic imaging ; pathology ; radiation effects ; Thyroid Hormones ; metabolism ; Thyroid Neoplasms ; metabolism ; pathology ; radiotherapy ; Treatment Outcome ; Yttrium Radioisotopes ; therapeutic use