A retrospective analysis of efficacy of systemic therapy in metastatic thyroid cancer

Objective: Thyroid cancer is the most common type of endocrine cancer. The current approaches in the systemic therapies of metastatic thyroid cancers are chemotherapy that is investigated in phase II clinical trials and tyrosine kinase inhibitors, investigated in phase III clinical trials. The aim of this study was to evaluate the efficacy of systemic therapies in metastatic thyroid cancer patients. Materials and Methods: We investigated 57 patients retrospectively, diagnosed with thyroid cancer who were referred to Maslak Acibadem Hospital Medical Oncology Department between 2008-2015 and Umraniye Training and Research Hospital between 2016-2018. They had received systemic treatment due to the refractory profile to radioiodine therapy and metastatic thyroid cancer. Results: Medical records of 57 patients with metastatic thyroid cancer, who were referred for systemic therapy were retrospectively analysed. 52% (n:30) of the cases were women and 48% (n:27) were men, and the mean age was 57.11 years. All patients was above the age of 18. Of the patients, 59.8% (n:35) had well differentiated thyroid cancer, 29.8% (n:17) had medullary thyroid cancer, 5.3% (n:3) had anaplastic thyroid cancer, 3.5% (n:2) had poorly differentiated thyroid cancer and 1.8% (n:1) had medullarypapillary synchronous cancer. When first line systemic therapy was evaluated for all 57 patients, progression free survival (PFS) was found 4.25 and 6.33 months for chemotherapy and sorafenib, respectively (P:0.035). All cases were evaluated retrospectively for second line systemic therapy and PFS was 4.1 and 7.77 months for chemotherapy and sorafenib, respectively (P<0.001). Conclusion: Tyrosine kinase inhibitors are used in the treatment of radioactive iodine-refractory differentiated thyroid cancers and medullary thyroid cancers. The effect of lenvatinib, sorafenib and vandetanib on progression-free survival in thyroid cancers is found to be superior to systemic chemotherapy. It was concluded that sorafenib is a systemic treatment option which can be preferred in terms of efficacy and toxicity profile in radioactive iodine refractory well-differentiated thyroid cancer especially in our country