Tumour Location Predicts Occult N1 Nodal Metastasis in Clinical Stage I Non-small Cell Lung Cancer


 
 
 Pathological lymph node metastases are often observed in patients with clinical N0 lung cancer. Identifying preoperative predictors of occult hilar nodal metastasis is important in determining the surgical procedure in patients with clinical stage I non-small cell lung cancer. This study aimed to determine the frequency and predictors of occult hilar nodal metastasis by tumour location in these patients.
 
 
 
 Between April 2007 and May 2019, data of patients who underwent lobectomy or segmentectomy for clinical stage I pure-solid non-small cell lung cancer were retrospectively reviewed. The ratio of the distance from the pulmonary hilum to the proximal side of the tumour to the distance from the pulmonary hilum to the visceral pleural surface through the centre of the tumour, named “distance ratio,” was calculated. The relationship of the distance ratio with clinicopathological findings and prognosis was discussed.
 
 
 
 A total of 357 patients were enrolled. Occult hilar nodal metastasis frequency was 14.6%. Patients were divided into two groups based on whether the distance ratio was ≤0.67 (central-type) or > 0.67 (peripheral-type). The frequency of occult hilar nodal metastasis was significantly higher in the distance ratio ≤0.67 group (21.5% vs 7.4%; P < 0.001). Multivariable analysis revealed that distance ratio was the only independent preoperative predictor of occult hilar nodal metastasis (odds ratio, 3.63; 95% confidence interval, 1.83–7.18; P < 0.001).
 
 
 
 The frequency of occult hilar nodal metastasis was significantly higher in peripheral-type lung cancer; therefore, tumour location was the most important preoperative predictor of occult hilar nodal metastasis.
