Sorafenib in metastatic radioactive iodine-refractory differentiated thyroid cancer: A pilot study

The incidence and mortality of thyroid cancer are on the increase worldwide and the treatment options for progressive, radioactive iodine (RAI)-refractory metastatic differentiated thyroid cancer (DTC) patients are currently limited. Sorafenib is a multikinase inhibitor that targets several molecular signals, which are believed to be involved in the pathogenesis of DTC. In this study, we reported our experience with the off-label use of sorafenib in Chinese cancer patients. A total of 8 patients (7 with papillary and 1 with follicular thyroid cancer) were recruited in this study. The partial response (PR) rate was 50.0% and 5 of the 8 patients (62.5%) achieved a durable response. The median progression-free survival (PFS) and overall survival (OS) were 40.1 and 55.0 weeks, respectively. Lung metastases were more sensitive to sorafenib compared to lymph nodes. The tumor marker response was not in accordance with the radiological response, although patients with tumor marker complete response (CR) exhibited a longer PFS and OS compared to those without a CR. Common adverse events (AEs) included palmar-plantar erythrodysesthesia, hypertension, diarrhea, weight loss and alopecia. Grade 4 AEs comprised hypocalcemia (1 patient) and elevated amylase levels (1 patient). A dose reduction was required in 62.5% of the patients. In conclusion, sorafenib exhibited a clinically relevant antitumor activity in patients with progressive metastatic RAI-refractory DTC, although the majority of the patients required a dose reduction due to intolerable toxicity.