Osseous Metastases in Thyroid Cancer: Unveiling Risk Factors, Disease Outcomes, and Treatment Impact

SIMPLE SUMMARY: Thyroid cancer is the most common endocrine cancer and is becoming increasingly prevalent. Although its prognosis is generally favorable, bone metastasis is a notable complication that significantly decreases survival rates. Currently, there is no definitive cure as most treatments are palliative to relieve patients of any pain or other symptoms. We assessed the incidence and influence of bone metastasis on thyroid cancer patients to understand the risk factors and outcomes which can improve clinical decision making and research endeavors. ABSTRACT: Bone is the second most common site of metastasis in patients with thyroid cancer (TC) and dramatically impacts overall survival and quality of life with no definitive cure, yet there is no extensive study of the demographic and clinical risk factors in the recent literature. Data regarding 120,754 TC patients with bone metastasis were retrieved from the Surveillance, Epidemiology, and End Results (SEER) database. Univariate and multivariate analyses were used to identify the risk factors of bone metastasis occurring in various histologies of TC. Cox regression was performed to analyze the influence of bone metastasis on overall survival. Hazard ratios were computed to analyze the association between bone metastasis and the primary outcomes. Of the 120,754 records collected from the SEER database from 2000 to 2019, 976 (0.8%) presented with bone metastasis, with occurrence being the greatest in patients of age ≥ 55 years (OR = 5.63, 95%CI = 4.72–6.71), males (OR = 2.60, 95%CI = 2.27–2.97), Blacks (OR = 2.38, 95%CI = 1.95–2.9) and Asian or Pacific Islanders (OR = 1.90, 95%CI = 1.58–2.27), and single marital status. TC patients presenting with bone metastasis (HR = 2.78, 95%CI = 2.34–3.3) or concurrent bone and brain metastases (HR = 1.62, 95%CI = 1.03–2.55) had a higher mortality risk. Older age, gender, race, and single marital status were associated with bone metastasis and poorer prognosis in TC patients at initial diagnosis. Understanding such risk factors can potentially assist clinicians in making early diagnoses and personalized treatment plans, as well as researchers in developing more therapeutic protocols.