Efficacy of sorafenib in advanced differentiated and medullary thyroid cancer: experience in a Turkish population

Background: Antivascular endothelial growth factor tyrosine kinase inhibitors have been used recently in the treatment of advanced differentiated thyroid cancer (DTC) and medullary thyroid cancer (MTC). Off-label sorafenib is used in Turkey with special permission by the Ministry of Health for this indication. Patients and methods: Patients with advanced DTC and MTC were retrospectively identified from the Turkish Ministry of Health database. Data on these patients were prospectively collected before permission is granted to use sorafenib. Results: Thirty patients with complete data were analyzed: 14 DTC (papillary number [n] = 10; follicular n=4) and 16 MTC. The median age of the patients was 57 years (range: 28-79 years), and there were 18 males and 12 females. All DTC patients were iodine refractory and had received a median three doses of radioactive iodine (range: 1-7 doses). Sorafenib was used for a median of 12 months (range: 1-49 months). The overall response rate was 20%, all partial responses, with no complete response. The overall response rate was 14% in DTC and 25% in MTC patients. The median progression-free survival (PFS) was 17.1 months (95% confidence interval [CI]: 7.3-26.8) and overall survival (OS) was not reached. The 2-year PFS and OS were 39% and 68%, respectively. DTC and MTC patients had similar survival outcomes: median PFS of 21.3 months (95% CI: 5.8-36.7) versus 14.5 months (95% CI: 3.7-25.2), respectively (P=0.36), with the median OS not reached in either group (P=0.17). Tumor marker levels did not have any prognostic or predictive role. The toxicity profile was similar to that of other sorafenib trials. Conclusion: Sorafenib is an effective and well-tolerated treatment in advanced thyroid cancers.