NODG-17 NUCLEAR THERANOSTICS FOR METASTATIC DEPOSITS TO THE CNS IN WELL-DIFFERENTIATED THYROID CANCER: AN EARLY REPORT FROM IBADAN

Abstract

Abstract Background and Aims Metastases to the central nervous system (CNS) from well-differentiated thyroid cancer (WDTC) are rare. This study aimed to describe the pattern of CNS involvement in WDTC and highlight the role of radioactive iodine (RAI)-based molecular imaging in patient management. Methods We retrospectively reviewed clinical records (2019–2024) to identify histologically confirmed WDTC cases referred for RAI theranostics, including molecular imaging and therapy. Seventeen patients with both histopathological and imaging evidence of CNS metastases were included. Demographic, clinicopathological, and imaging data were analyzed. Results CNS metastases were identified in 9.7% of WDTC patients. The M: F was 1:7.5, with 35.3% under 55 years of age. Histologic subtypes included follicular (70.6%) and papillary (29.4%) carcinoma. Metastatic distribution was cranial (64.7%), spinal (58.8%), and combined cranial-spinal (23.5%). Neurological symptoms were present in 76.5% of patients, most commonly difficulty in walking (47.1%) and headaches (17.6%). Neurosurgical intervention was performed in 47.1% of cases and of these, delayed presentation (62.5%), poor performance status (ECOG PS 3–4 in 62.5%), and extensive cranial disease (25%) limited immediate RAI therapy eligibility. RAI therapy benefited 23.5% of patients—half of whom underwent prior neurosurgical decompression, leading to improved ECOG PS. Notably, RAI molecular imaging detected asymptomatic CNS metastases in 11.7% of patients with normal anatomical imaging. Conclusion CNS metastases from WDTC, though uncommon, may be increasingly encountered. RAI-based molecular imaging is critical for detecting occult metastases missed on conventional imaging. Early identification and neurosurgical intervention can improve patient selection for RAI therapy, reinforcing the value of a precision medicine approach in optimizing outcomes.