Prognostic indicators of outcomes in patients with lung metastases from differentiated thyroid carcinoma during long-term follow-up.

Abstract

Distant metastases, although uncommon, represent maximum disease-related mortality in differentiated thyroid carcinoma (DTC). Lungs are the most frequent sites of metastases. We aimed to evaluate long-term outcomes and identify prognostic factors in metastatic DTC limited to the lungs. This retrospective study included 89 patients with DTC and metastases limited to the lungs, who were treated between 1996 and 2012 at Samsung Medical Center. Progression-free survival (PFS) and cancer-specific survival (CSS) rates were evaluated according to clinicopathologic factors. Cox regression analysis was used to identify independent factors associated with structural progressive disease (PD) and cancer-specific death. With a median follow-up of 84months, the 5- and 10-year CSS rates were 78% and 73%, respectively. Older age at diagnosis (≥55years), radioactive iodine (RAI) nonavidity, preoperative or late diagnosis of metastasis and macro-nodular metastasis (≥1cm) were predictive of decreased PFS and CSS. Multivariate analysis identified older age (P=.002), RAI nonavidity (P=.045) and preoperative (P=.030) or late diagnosis (P=.026) as independent predictors of structural PD. RAI avidity was also independent predictor of cancer-specific death (P=.025). Patients with DTC and metastatic disease limited to the lungs had favourable long-term outcomes. Age, RAI avidity and timing of metastasis were found to be major factors for predicting prognosis.