Clinicopathological characteristics and long-term outcome in patients with distant metastases from differentiated...

Distant metastases are seen in a minority of patients with differentiated thyroid carcinoma (DTC) but account for most of its disease-specific mortality. Studies on the long-term outcome of patients with distant metastases are controversial.

We retrospectively reviewed the medical records of 660 patients with differentiated thyroid carcinoma followed at our institution from 1994 to 2004. Forty-four patients (6.7%) had distant metastases, with a prevalence of 4.8% for papillary thyroid cancer, 21% for follicular thyroid cancer, and 10% for Hurthle cell cancer. Primary near-total thyroidectomy followed by I(131) radiation was performed in 97% of patients with metastases (86% operated on in 1980-2003). Mean age at thyroidectomy was 49+/-19 years, and the female-to-male ratio was 1.9:1.

The distant metastasis occurred synchronously with the primary tumor in 45.5% and after a median follow-up of 9 years in the others. Affected sites were lungs (n=24), bones (n=11), lungs and bones (n=9), brain (n=3), and uterus (n=1). Median duration of follow-up was 12 years (range: 1-42 years) from thyroidectomy and 5.5 years (range: 1-24 years) from diagnosis of distant metastases. The 5- and 10-year survival rates (all causes) after diagnosis of distant metastases were 88% and 77%, respectively. No significant differences in survival curves were found by age, sex, metastasis site, histopathology, or interval to distant metastasis.

We conclude that complete resection of the thyroid gland at diagnosis and high-dose adjuvant radioactive iodine are associated with improved survival in patients with metastatic DTC.