Abstract
OBJECTIVE: Although the lung is the most common site of thyroid cancer metastasis, limited evidence of pulmonary metastasectomy is available. This study aimed to review the clinical course and outcomes of patients who underwent complete resection of solitary pulmonary metastases appearing during a watchful-waiting period. METHODS: We retrospectively reviewed 11 patients with pulmonary metastases from thyroid cancer who underwent pulmonary metastasectomies between January 2000 and December 2023 at Osaka International Cancer Institute. RESULTS: The median patient age was 73 years. Eight patients had differentiated thyroid carcinoma (DTC), and three had non-DTC. All patients had previously undergone complete resection of their primary disease. The solitary pulmonary nodules were detected during the watchful-waiting period, with six preoperatively diagnosed as primary lung cancer and five as pulmonary metastases. All patients underwent complete resection of the pulmonary nodules, with intraoperative diagnoses confirmed in 10 cases. Among the patients with DTC, four patients experienced relapse-free survival for at least 66 months without the need for additional systemic therapy after pulmonary metastasectomy. The remaining three patients also survived without recurrence during the postoperative watchful-waiting period. In contrast, among the three patients with non-DTC, only one patient underwent repeated PM and achieved 47 months of disease control, while the other two patients experienced earlier recurrence. CONCLUSIONS: Although our data were limited to definitively conclude the efficacy of completely resecting solitary metastases, surgical resection could be recommended for a definitive diagnosis and potentially extending relapse-free survival in patients with DTC. However, given the poor and heterogeneous outcomes in non-DTC, the indication for PM should be carefully considered on a case-by-case basis. (263/350 words).