title: Central tumour location should be considered when comparing N1 upstaging between thoracoscopic and open surgery for clinical stage I non-small-cell lung cancer.
abstract: OBJECTIVE
  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 [(18)F]-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.
authors.affiliation: Department of Thoracic Surgery, University Hospitals Leuven, Leuven, Belgium Department of Clinical and Experimental Medicine, KU Leuven, Leuven, Belgium herbert.decaluwe@uzleuven.be.
authors.forename: Herbert
authors.initials: H
authors.lastname: Decaluwé
authors.affiliation: Department of Thoracic Surgery, University Hospitals Leuven, Leuven, Belgium Department of Clinical and Experimental Medicine, KU Leuven, Leuven, Belgium.
authors.forename: Alessia
authors.initials: A
authors.lastname: Stanzi
authors.affiliation: Department of Pulmonology, University Hospitals Leuven, Leuven, Belgium.
authors.forename: Christophe
authors.initials: C
authors.lastname: Dooms
authors.affiliation: Leuven Biostatistics and Statistical Bioinformatics Centre (L-Biostat), Leuven, Belgium.
authors.forename: Steffen
authors.initials: S
authors.lastname: Fieuws
authors.affiliation: Department of Thoracic Surgery, University Hospitals Leuven, Leuven, Belgium Department of Clinical and Experimental Medicine, KU Leuven, Leuven, Belgium.
authors.forename: Willy
authors.initials: W
authors.lastname: Coosemans
authors.affiliation: Department of Thoracic Surgery, University Hospitals Leuven, Leuven, Belgium Department of Clinical and Experimental Medicine, KU Leuven, Leuven, Belgium.
authors.forename: Lieven
authors.initials: L
authors.lastname: Depypere
authors.affiliation: Department of Nuclear Medicine, University Hospitals Leuven, Leuven, Belgium.
authors.forename: Christophe M
authors.initials: CM
authors.lastname: Deroose
authors.affiliation: Department of Radiology, University Hospitals Leuven, Leuven, Belgium.
authors.forename: Walter
authors.initials: W
authors.lastname: Dewever
authors.affiliation: Department of Thoracic Surgery, University Hospitals Leuven, Leuven, Belgium Department of Clinical and Experimental Medicine, KU Leuven, Leuven, Belgium.
authors.forename: Philippe
authors.initials: P
authors.lastname: Nafteux
authors.affiliation: Department of Radiation Oncology, University Hospitals Leuven, Leuven, Belgium.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Peeters
authors.affiliation: Department of Thoracic Surgery, University Hospitals Leuven, Leuven, Belgium Department of Clinical and Experimental Medicine, KU Leuven, Leuven, Belgium.
authors.forename: Hans
authors.initials: H
authors.lastname: Van Veer
authors.affiliation: Department of Pathology, University Hospitals Leuven, Leuven, Belgium.
authors.forename: Eric
authors.initials: E
authors.lastname: Verbeken
authors.affiliation: Department of Thoracic Surgery, University Hospitals Leuven, Leuven, Belgium Department of Clinical and Experimental Medicine, KU Leuven, Leuven, Belgium.
authors.forename: Dirk
authors.initials: D
authors.lastname: Van Raemdonck
authors.affiliation: Department of Thoracic Surgery, University Hospitals Leuven, Leuven, Belgium Department of Clinical and Experimental Medicine, KU Leuven, Leuven, Belgium.
authors.forename: Johnny
authors.initials: J
authors.lastname: Moons
authors.affiliation: Department of Thoracic Surgery, University Hospitals Leuven, Leuven, Belgium Department of Clinical and Experimental Medicine, KU Leuven, Leuven, Belgium.
authors.forename: Paul
authors.initials: P
authors.lastname: De Leyn
mesh_terms: D000368:Aged; D002289:Carcinoma, Non-Small-Cell Lung / Q000601:surgery*; D061887:Conversion to Open Surgery; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000601:surgery*; D008207:Lymphatic Metastasis; D008297:Male; D000072662:Margins of Excision; D009367:Neoplasm Staging; D011446:Prospective Studies; D020775:Thoracic Surgery, Video-Assisted / Q000379:methods*; D013906:Thoracoscopy / Q000379:methods*; D013908:Thoracotomy / Q000379:methods
keywords: Central tumour; Lung cancer; N1; NSCLC; Nodal upstaging; VATS