Successful use of sorafenib after bortezomib failure in metastatic follicular thyroid cancer - a case report.

Background: Thyroid cancer (TC) is the most commonly diagnosed endocrine malignancy in developed countries. Differentiated thyroid carcinoma (DTC), which includes papillary thyroid carcinoma and follicular thyroid carcinoma (FTC), composes more than 90% of all TC cases. When DTC recurs or metastasizes to distant sites despite the use of local and radiotherapeutic treatment modalities, the currently effective treatment options are limited.

Case report: A then 40-year-old female Caucasian patient was diagnosed with FTC and underwent surgery and postoperative radioactive iodine therapy. The patient developed metastatic disease, and palliative first-line treatment with the proteasome inhibitor bortezomib was initiated. After 3 months, the patient suffered progressive pulmonary metastatic disease. Treatment with the multikinase inhibitor sorafenib was started, and after 3 months of therapy, tumor restaging demonstrated partial remission. The treatment is ongoing, and the current progression-free survival is 16 months. With the exception of mild diarrhea and hand-foot syndrome, the therapy was well tolerated, and no grade 3/4 adverse toxicities occurred.

Conclusion: In our single case of metastatic FTC, sorafenib showed clinically meaningful antitumor activity accompanied by good tolerability. This case report supports the use of this drug as a potential treatment option for advanced/metastatic FTC.