Abstract：
OBJECTIVE: Pulmonary lymphatic drainage of the lower lobe into the mediastinal lymph nodes includes not only the pathway via the hilar lymph nodes but also the pathway directly into the mediastinum via the pulmonary ligament. This study aimed to determine the association between the distance from the mediastinum to the tumor and the frequency of occult mediastinal nodal metastasis (OMNM) in patients with clinical stage I lower-lobe non-small cell lung cancer (NSCLC).
METHODS: Between April 2007 and March 2022, data of patients who underwent anatomical pulmonary resection and mediastinal lymph node dissection for clinical stage I radiological pure-solid lower-lobe NSCLC were retrospectively reviewed. In computed tomography axial sections, the ratio of the distance from the inner edge of the lung to the inner margin of the tumor within the lung width of the affected lung was defined as the inner margin ratio. Patients were divided into 2 groups based on whether the inner margin ratio was ≤0.50 (inner-type) or >0.50 (outer-type), and the association between inner margin ratio status and clinicopathological findings was assessed.
RESULTS: In total, 200 patients were enrolled in the study. OMNM frequency was 8.5%. More inner-type than outer-type patients had OMNM (13.2% vs 3.2%; P = .012) and skip N2 metastasis (7.5% vs 1.1%; P = .038). Multivariable analysis revealed that the inner margin ratio was the only independent preoperative predictor of OMNM (odds ratio, 4.72; 95% CI, 1.31-17.07; P = .018).
CONCLUSIONS: Tumor distance from the mediastinum was the most important preoperative predictor of OMNM in patients with lower-lobe NSCLC.
METHODS: Between April 2007 and March 2022, data of patients who underwent anatomical pulmonary resection and mediastinal lymph node dissection for clinical stage I radiological pure-solid lower-lobe NSCLC were retrospectively reviewed. In computed tomography axial sections, the ratio of the distance from the inner edge of the lung to the inner margin of the tumor within the lung width of the affected lung was defined as the inner margin ratio. Patients were divided into 2 groups based on whether the inner margin ratio was ≤0.50 (inner-type) or >0.50 (outer-type), and the association between inner margin ratio status and clinicopathological findings was assessed.
RESULTS: In total, 200 patients were enrolled in the study. OMNM frequency was 8.5%. More inner-type than outer-type patients had OMNM (13.2% vs 3.2%; P = .012) and skip N2 metastasis (7.5% vs 1.1%; P = .038). Multivariable analysis revealed that the inner margin ratio was the only independent preoperative predictor of OMNM (odds ratio, 4.72; 95% CI, 1.31-17.07; P = .018).
CONCLUSIONS: Tumor distance from the mediastinum was the most important preoperative predictor of OMNM in patients with lower-lobe NSCLC.
摘要：
目的：下叶肺淋巴引流到纵隔淋巴结不仅包括通过肺门淋巴结的途径，还包括通过肺韧带直接进入纵隔的途径。这项研究旨在确定从纵隔到肿瘤的距离与隐匿性纵隔淋巴结转移（OMNM）的频率之间的关系。
方法：在2007年4月至2022年3月之间，回顾性分析了因临床I期放射学纯实性下叶NSCLC而接受解剖性肺切除术和纵隔淋巴结清扫术的患者数据。在计算机断层扫描轴向切片中，在受影响肺的肺宽度内,从肺内缘到肿瘤内缘的距离之比定义为内缘比(IMR).根据IMR≤0.50（内型）或>0.50（外型）将患者分为两组，并评估了IMR状态与临床病理结果之间的关联。
结果：总计，200名患者被纳入研究。OMNM频率为8.5%。内型患者的OMNM高于外型患者(13.2%vs.3.2％；P=0.012）和跳过N2转移（7.5％vs.1.1%;P=0.038)。多变量分析表明，IMR是OMNM的唯一独立术前预测因子(比值比，4.72；95%置信区间，1.31-17.07；P=0.018）。
结论：肿瘤距纵隔的距离是下叶非小细胞肺癌患者OMNM的最重要的术前预测因子。
方法：在2007年4月至2022年3月之间，回顾性分析了因临床I期放射学纯实性下叶NSCLC而接受解剖性肺切除术和纵隔淋巴结清扫术的患者数据。在计算机断层扫描轴向切片中，在受影响肺的肺宽度内,从肺内缘到肿瘤内缘的距离之比定义为内缘比(IMR).根据IMR≤0.50（内型）或>0.50（外型）将患者分为两组，并评估了IMR状态与临床病理结果之间的关联。
结果：总计，200名患者被纳入研究。OMNM频率为8.5%。内型患者的OMNM高于外型患者(13.2%vs.3.2％；P=0.012）和跳过N2转移（7.5％vs.1.1%;P=0.038)。多变量分析表明，IMR是OMNM的唯一独立术前预测因子(比值比，4.72；95%置信区间，1.31-17.07；P=0.018）。
结论：肿瘤距纵隔的距离是下叶非小细胞肺癌患者OMNM的最重要的术前预测因子。
