First-line targeted treatment for radioactive iodine-refractory metastatic thyroid cancer: systemic literature review and network metaanalysis

초록

Background Differentiated thyroid cancers (DTC), which include papillary, follicular and poorly differentiated subtypes constitutes 90% of all thyroid malignancies. DTC have generally an excellent outcome after the traditional treatment which includes, surgery, thyroid stimulating hormone (TSH) suppression therapy, and radioactive iodine (RAI) therapy, and in some cases radiation therapy. However, the 10-year survival rate among patients with differentiated thyroid cancer that is refractory to radioiodine therapy is 10% from the time of detection of metastasis. Systemic chemotherapy has been found relatively ineffective with poor response rates. There are limited options for treatment of patients with radioactive iodine refractory, progressive differentiated thyroid cancer. Recent advances in understanding of oncogenic pathways of thyroid cancers have enabled the development of targeted therapies for metastatic thyroid cancer. During the last decade, aberrant signaling pathways have been investigated in the development, progression, and metastasis of DTC such as BRAF and RAS point mutations and rearrangement of the RET proto-oncogene in papillary cancers. Based on current treatment guideline, anti-VEGF targeted treatment is mainly recommended as category 1 treatment option for metastatic radioactive iondine-refractory differentiated thyroid cancer. Because these kinds of drugs underwent simultaneous clinical development, there are no direct efficacy and safety comparison. Our study was conducted to determine the ranking of the targeted agents and to compare efficacy of all available treatments Material and Methods We performed systemic literature review and a network meta-analysis to identify all eligible randomized clinical trials evaluating the outcomes of metastatic differentiated thyroid cancer patients treated with targeted agent as first-line treatment. Eligible studies had to be either complete reports of prospective, randomized controlled tr