Metastases to the Thyroid Gland: What Can We Do?

Simple Summary To better improve the clinical diagnosis and treatment of thyroid metastatic cancer, minimize morbidity and mortality, and improve the prognosis of patients, in this paper, we review the research status of thyroid metastatic cancer. Metastases to the thyroid gland itself are not common, and the clinical manifestations are not specific. Most of the primary tumors originate from the kidney, colorectum, lung, and breast. FNAB combined with IHC analysis is a specific method for the diagnosis of secondary thyroid neoplasms, and besides having high accuracy, it can also distinguish the primary location of the tumor. Surgical treatment is still the main treatment, supplemented by necessary radiotherapy and chemotherapy after surgery. The treatment plan for patients should be individualized and jointly developed by a multidisciplinary team. The prognosis of patients with thyroid metastatic cancer is still not optimistic. Therefore, we believe that when thyroid abnormalities are found in patients with previous or present malignant tumors, the possibility of metastases to the thyroid gland should be considered first. Metastases to the thyroid gland arise from other malignant tumors such as renal cell carcinoma, colorectal cancer, lung cancer, and breast cancer. In clinical practice, the incidence is low, and the symptoms are not specific, so it is often missed and misdiagnosed. It is finally diagnosed via the comprehensive application of many diagnostic methods, such as ultrasound, fine-needle aspiration biopsy, and immunohistochemistry analysis. Surgery-based comprehensive treatment is often adopted, but because it is usually in the late stage of the primary tumor, the prognosis is poor. In order to better understand the related characteristics of thyroid metastatic cancer and then improve the clinical diagnosis and treatment and the prognosis of patients, in this paper, we systematically summarize the research status of thyroid metastatic cancer.