Differentiated Thyroid Carcinoma Presenting Distant Metastses as a Initial Sign

ABSTRACT

PURPOSE: Distant metastases, as the initial sign of a differentiated thyroid carcinoma, are extremely rare. The clinical characteristics for such cases remain to be established. This study was performed to characterize the clinical presentation, treatments, and outcome in such patients. METHODS: Between January 1986 and February 2005, of 4,525 differentiated thyroid cancer patients, 18 presented with distant metastases as the initial sign (0.4%). These comprised of 6 men and 12 women, with a median age of 49 years (range 9~66). Of the 18 patients, 8 (44.4%), 7 (38.9%), and 3 (16.7%) disclosed symptoms from lung, bone, and brain (16.7%) metastases, respectively. The median follow-up was 92 months, ranging from 18 to 198. RESULTS: The symptoms included cough and sputum (n=5), hemoptysis (n=2) and a lung mass (n=1) from lung metastases, back pain (n=3), a palpable mass (n=2) and a pathologic fracture (n=2) from bone metastases, as well as a headache with nausea (n=3) in all cases with brain metastases. The sites of metastases were the lung only in 7 (38.9%), bone only in 7 (38.9%) and multi-organ in 4 (22.2%). The histological diagnoses were a papillary carcinoma in 10 and a follicular carcinoma in 8. All patients underwent a total thyroidectomy followed by therapeutic radio-iodine therapy (RAI) and TSH suppressive treatment. For the metastatic lesions, aggressive treatment modalities, including surgical resection (n=9), external beam radiation (n=11), gamma-knife surgery (n=1) and a combination of these, were performed. The 10 year overall and disease-free survivals were 91.7 and 51.4%, respectively. There was only one disease-related death (1.6%). Tumor multiplicity (p=0.023) and multi-organ metastasis (p=0.009) were significant predictors of a poor prognosis. CONCLUSION: Clinical symptoms, history, physical examination, imaging studies and histological confirmation of distant metastatic lesions are important in the initial diagnostic approach. Even though distant metastasis presented as the initial sign, a 10-year disease-free survival rate of 50% was obtained. Radical resection of primary and metastatic lesions combined with high dose RAI treatment and/or external irradiation lead to long-term survival.