Clinical and Morphological Characteristics of Patients with Brain Metastases of Papillary Thyroid Carcinoma

Abstract

Introduction. As a rule, papillary thyroid carcinoma (PTC) is associated with lymph node metastases, while distant organ involvement such as the lungs and skeletal bones being relatively rare. Cerebral metastases are exceptionally rare, limited to individual case reports or small case series, including 5-10 patients each.

Material and methods. Over a 30-year observation period, according to the Belarusian Cancer Registry, 5 male and 6 female patients aged 38 to 74 years at the onset of PTC treatment, and one pediatric patient (female) from a total of 1641 patients aged 18 or younger, were identified with confirmed brain metastases either at the initial stages of treatment or during the follow-up.

Results. The disease course was less favorable in men, they succumbed to relapse/progression more frequently after primary tumor treatment (p = 0.003) and had reduced survival rates following brain involvement (p = 0.059). Local tumor extent, specifically pT3-T4 staging, was associated with a significantly increased risk of recurrences/progression (p = 0.04) and decreased survival rates (p = 0.034). Patients with distant metastases had an elevated risk of PTC relapse/progression (p = 0.027). However, the presence of organ-specific metastases did not affect tumor-specific survival rates (p > 0.05). Treatment approaches after diagnosing cerebral metastases varied, but patients who underwent radiation therapy or radiation iodine therapy, either as monotherapy or in combination with chemotherapy or as part of multimodal treatment, had better survival rates (p = 0.022).

Conclusions. This study presents a detailed clinical and morphological characterization of 12 patients with cerebral metastases from PTC, which either developed after radical treatment for the primary tumor or presented as the initial manifestation of the disease. We provided recommendations for the timely detection of tumors in such atypical locations. CT/MRI of the brain should also be included in the diagnostic plan for patients with distant metastases to the lungs and/or bones (at any stage of the disease) for the prompt diagnosis of potentially life-threatening intracranial metastases.