Incidence and Survival of Thyroid Cancer with Lung Metastasis

Abstract

Background: Thyroid cancer (TC) is common malignancy. Lung metastasis is one of the top metastases for TC. The incidence and survival rates of TC with lung metastasis remains unclear.Methods: Data on TC with lung metastasis and other site-specific metastases were extracted from the Surveillance, Epidemiology, and End Results (SEER) database. The chi-square tests were employed to compare the clinicopathological characteristics among patients with different sites of metastases. Kaplan-Meier analysis and log-rank tests were used for survival analysis. A Cox proportional model was used for multivariate analyses of the patient population. Statistical significance indicated by a two-tailed P value < 0.05. Results: A total of 77322 patients with TC and known sites of distant metastases 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 and thyroid cancer-specific survival compared to patients with isolated bone metastases (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 overall survival or thyroid cancer specific survival 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 compared to patients with isolated bone metastases and liver metastases, whereas is similar to brain metastasis. There was the worst survival outcome on patients with multi-organ metastases.