Endocrine Abstracts

Introduction: Radioactive iodine-refractory differentiated thyroid cancer is a rare form of advanced thyroid cancer (approximately 4 cases per million population per year) defined by persistent disease after administration of a cumulative radioiodine dose of 600 mCi or at least one tumor without radioactive iodine uptake or by progression of the disease within one year after RAI treatment. Therapeutic options in this case include molecular-targeted therapies, like tyrosine kinase inhibitors, selective BRAF inhibitors, treatments directed at the VEGFR and even immunotherapy that may control thyroid progression and prolong progression-free survival.

Case Report: We present the case of a 69 year old female who was admitted in our endocrinology department with history of papillary thyroid carcinoma for which she had undergone total thyroidectomy in 2007, followed by three surgical reinterventions for local regrowth in 2011, 2013, 2014 and a cumulative dose of 1200 mCi of radioiodine. A CT scan performed in March 2018 identified a cervical tumor of 33/20/30 mm that which grew up to 23.2/54.5 mm during the next 6 months, associated with multiple metastases in local lymph nodes and both lungs. At that point a new surgery was refused by the patients. Taking into account the progression of the disease despite high cumulative dose of radioiodine already received by the patient there was no indication for I131 treatment. In this scenario, indication for thyrosine kinase inhibitor was recommended so the patient received 400 mg of sorafenib per day. In January 2019, at 3 months of therapy, she had clinically local progression of the disease and the CT scan shows a tumor of 43.4/54.8 mm with massive intra-tumoral necrosis and persistent lymph nodes and pulmonary metastases with newly developed left pleuresy. The thyroglobulin levels under LT4 treatment decreased 3 months of sorafenib from 4034 ng/ml to 2277 ng/ml.

Discussion: Despite significant reduction of thyroglobulin levels and tumor necrosis after 3 month of tyrosine kinase inhibitors that would make our patient a good responder, the local progression of the disease in the surrounding tissue will have an important impact on the patients’ survival.