Incidence and Survival of Thyroid Cancer with Lung Metastasis

Abstract

Background: Thyroid cancer (TC) is a common malignancy. Lung metastasis is one of the top metastases for TC. The incidence and survival rates of TC with lung metastasis remain unclear.Methods: Data on TC with lung metastasis and other site-specific metastases were extracted from the Surveillance, Epidemiology, and End Results (SEER) database. Chi-square tests were employed to compare the biological and clinical features of thyroid patients with different metastatic sites. Survival analysis was performed utilizing Kaplan-Meier analysis and log-rank tests. We used a Cox proportional hazards model for the multivariate analysis to identify prognostic factors of thyroid patients with lung metastases. Statistical significance was indicated by a two-tailed P value < 0.05.Results: A total of 77322 patients suffering from TC with clear metastasis information were identified from 2010-2016. The probability of isolated lung metastasis was significantly higher than that of isolated distant metastasis to other sites among TC patients (P < 0.05). Patients with isolated lung metastases had worse overall survival (OS) and thyroid cancer-specific survival (TCSS) than patients with bone metastasis only (P < 0.05). There was a slight difference in thyroid cancer-specific survival between patients with lung metastasis and patients with liver metastasis (P=0.0496), while there was no significant difference in overall survival. (P >0.05). There was no significant difference in OS or TCSS between patients with lung metastasis and those with brain metastasis (P > 0.05). Multivariate analysis revealed that white race was associated with better outcomes in terms of both endpoints in the lung metastasis population.Conclusions: The incidence of lung metastasis from TC was higher than that of other organ metastases. Thyroid cancer patients with isolated lung metastases have worse outcomes than patients with isolated bone metastases and liver metastases but are similar to brain metastases. There was the worst survival outcome in patients with multiorgan metastases.