Clinical outcomes of a cohort of 271 patients with lung metastases from differentiated thyroid carcinoma.

Abstract

Lung is the most common site of distant metastases from differentiated thyroid carcinoma (DTC). To investigate the outcomes of a cohort of patients with DTC and lung metastases (LM). A retrospective analysis of a cohort of 271 patients with LM was performed. The female-to-male ratio was 1:1 and the median follow-up time was 5.9 (1.1-38.4) years. Papillary thyroid carcinoma (PTC) was the most frequent type (83.4%), mainly the classic variant, followed by follicular thyroid carcinoma (FTC, 10.3%) and Hürthle cell carcinoma (HTC, 6.3%). The prevalence of PTC, FTC and HCC was different between the micronodular and macronodular LM groups [87.4%, 6.3% and 6.3% vs. 74.6%, 19.0% and 6.3%, respectively (p = .013)]. Only 5.0% of the patients had LM diagnosed after a period of remission. LM were submitted to radioactive iodine treatment (RAIT) in 84.5% (52.8% showed 131 iodine avid metastases). Complete remission was only achieved in 12.2%. Micronodular disease and age <55 years at LM diagnosis were associated with a better prognosis (p < .05). We found no difference in survival between patients with LM treated or not with RAIT. However, in patients submitted to RAIT, there was a tendency for longer survival in the group of patients with 131 I avid lesions. The classic variant of PTC was the most frequent histology found in LM of DTC. LM are rarely diagnosed in the follow-up when complete remission is achieved after surgery and 131 I. Younger age at LM diagnosis and a micronodular pattern are associated with a better prognosis.