Prognostic significance of lung metastasis-related finding in lenvatinib treatment for differentiated thyroid cancer

This study aimed to analyze the clinical course of patients with differentiated thyroid cancer (DTC) who were treated by lenvatinib and investigate the specific criteria for the initiation of lenvatinib in lung metastasis.

A total of 111 patients with DTC treated by lenvatinib were included in the study. Patients were divided into two groups based on the target lesion for the initiation of lenvatinib: lung metastasis group and other metastases group.

In the univariate analysis, the tumor size for the lung metastasis (p = 0.002) and the factor of lung metastasis group (p < 0.001) were significantly associated with overall survival (OS). Multivariate analysis revealed that the factor of lung metastasis group [hazard ratio, 0.408; 95% confidence interval (CI), 0.206–0.810; p = 0.010] was the only independent prognostic factor of OS. Of the 53 patients in the lung metastasis group, 12 (23%) had lung metastasis-related finding such as pleural effusion (n = 12), hemoptysis (n = 2), and dyspnea (n = 1) at the initiation of lenvatinib treatment. The median OS in patients with or without lung metastasis-related findings were 41.0 [95% CI, 10.4–not available (NA)] months and 62.9 (95% CI, 53.0–NA) months, respectively (p = 0.022).

Patients with lung metastasis-related finding at the initiation of lenvatinib treatment had a poorer prognosis among the lung metastasis group. It is important to consider not only the tumor size but also the presence of lung metastasis-related findings when initiating lenvatinib treatment for DTC patients with lung metastasis.