Nodal upstaging is a quality indicator for oncological thoracic surgery and is found in up to 25% of patients with clinical stage I (cStage-I) non-small-cell lung cancer (NSCLC). In large retrospective series, lower N1 upstaging was reported after video-assisted thoracic surgery (VATS) resections. We studied the impact of central primary tumour location on nodal upstaging in cStage-I NSCLC.METHODS
Consecutive patients operated for cStage-I NSCLC were selected from a prospectively managed surgical database. Tumour location was classified as central if the lesion was visible during standard video bronchoscopy. A nodal station mapping was drawn for each patient based on final pathological examination. Univariable and additive multivariable binary logistic regression analyses were performed.RESULTS
Between 2007–2014, 334 patients underwent anatomical resection for cStage-I NSCLC, either by open thoracotomy (n = 158) or by VATS (n = 176; conversion rate 1.7%). All patients underwent imaging with [18F]-fluorodeoxyglucose positron emission tomography and computer tomography. Invasive mediastinal staging was performed in 24.6% of patients. There were more central tumours in the open group (24.1%, n = 38) compared with the VATS group (4.5%, n = 8). There was no significant difference between the number (mean ± standard deviation) of nodal stations examined (open 5 ± 1.9 vs VATS 5 ± 1.7, P = 0.99). Pathological nodal upstaging was found in 15.9% (n = 53) of cStage-I patients. Nodal pN1 and pN2 upstaging were 13.3 and 8.2%, respectively, for the open group, and 6.3 and 4.5%, respectively, for the VATS group. In 32.6% (n = 15/46) of patients with a central cStage-I tumour pN1, upstaging was found. A binary logistic regression model (including tumour location, technique, tumour size, gender and histology) showed that only tumour location had a significant impact on pN1 upstaging [peripheral versus central; odds ratio (OR) 5.07 (confidence interval, CI: 1.89–13.60), P = 0.001], while surgical technique had no significant impact [VATS versus open; OR 0.74 (CI: 0.31–1.78), P = 0.50].CONCLUSIONS
The number of lymph node stations examined during VATS resections is similar to open resections for cStage-I NSCLC. Almost one-third of the patients with a central cStage-I NSCLC were upstaged to pN1. Tumour location was the only independent variable for pN1 upstaging in logistic regression analysis. It is a potential bias in retrospective studies and should therefore be accounted for when comparing different surgical resection techniques for cStage-I NSCLC.