Targeted radionuclide therapy for patients with metastatic medullary thyroid carcinoma

Objective To evaluate the effect of 90Y-DOTATOC and 131I-MIBG in treatment of metastatic medullary thyroid carcinoma ( MTC ). Methods Twelve histologically confirmed patients with metastatic MTC were included. All patients underwent both 111in-DTPA-octreotide imaging and131 I/1231-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) or131I-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. Results 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 90 Y-DOTATOC, and five patients with 131I-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. Conclusion The combined imaging technique can be used to identify patients for effective radionuclide treatment. The treatment with 90Y-DOTATOC or 131 I-MIBG is well tolerated and may improve the fate of patients with metastatic MTC.