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Is extrathoracic metastasis screening necessary for clinical stage IA non-small cell lung cancer?

BACKGROUND
Detecting distant metastases when staging lung cancer is critical to avoid unnecessary surgery and provide appropriate multidisciplinary treatment. However, it is controversial as to whether staging studies should be performed routinely for patients with early-stage lung cancer who have no evidence of distant metastasis. Thus, this study aimed to examine the need for extrathoracic metastasis screening in patients with clinical stage IA non-small cell lung cancer, understand the association between extrathoracic metastasis and other clinical features, and evaluate the diagnostic efficiency of imaging screening for preoperative extrathoracic metastasis in patients with early-stage lung cancer.


METHODS
From 2010 to 2019, 510 patients diagnosed with clinical T1N0 lung cancer, excluding contralateral lung metastases, pleural dissemination, malignant pleural effusion, and malignant pericardial effusion, were treated for primary lung cancer. Patients were divided into two groups, and their clinicopathological characteristics were investigated.


RESULTS
Five patients (1.0%) had extrathoracic metastases. The histological types were adenocarcinoma in three of the cases, and squamous cell carcinoma and large cell neuroendocrine carcinoma in the other two cases. The T factor was T1b in one case and T1c in four cases. Four patients had solid tumors and one had a solid predominant tumor with an average tumor diameter of 23.0 ± 2.9 mm. The size of solid tumors with extrathoracic metastases was larger than their counterparts.


CONCLUSION
When evaluating stage IA non-small cell lung cancer with a solid component diameter < 22 mm, or clinical T1mi-1bN0 in computed tomography evaluation, screening for preoperative extrathoracic metastasis may be omitted.