title: The intrathoracic lymph node ratio seems to be a better prognostic factor than the level of lymph node involvement in lung metastasectomy of colorectal carcinoma.
abstract: OBJECTIVE
  Data on thoracic lymph node involvement (LNI) in lung metastasis of colorectal cancer (CRC) are conflicting, with a 5-year overall survival (OS) ranging from 6 to 40%. We aimed to evaluate whether there are subgroups of patients according to the lymph node ratio (LNR).
  
  
  METHODS
  We retrospectively reviewed the data from 106 patients who underwent a thoracic procedure for CRC lung metastasis with pathologically proven thoracic LNI.
  
  
  RESULTS
  In the univariate analysis, the median OS was significantly poorer for a pN2 location of LNI (26 vs 16 months, P = 0.04), LNR ≥50% (30 vs 17 months, P = 0.005), high preoperative CEA (32 vs 16 months, P = 0.02), hepatic metastases (27 vs 11 months, P <0.0001) and disease-free survival < 24 months (32 vs 17 months, P = 0.05). When pN1 and pN2 patients were staged according to the LNR, the median OS was significantly better for an LNR <50% (27 vs 17 months for pN1, 32 vs 12 months for pN2, P = 0.01). In the multivariate analysis, a high preoperative CEA [hazard ratio (HR): 2.256 (1.051-4.841), P = 0.04], pN1 status [HR: 0.337 (0.162-0.7), P = 0.004] and the absence of hepatic metastases [HR: 0.395 (0.180-0.687), P = 0.02] remained significant prognostic factors. There was an upward trend for patients with LNR <50% [HR: 0.565 (0.296-1.082), P = 0.08]. Otherwise, low LNR was significantly associated with a decreased risk of loco-regional recurrence (HR: 0.36, 95% confidence intervals: 0.14-0.96, P = 0.04).
  
  
  CONCLUSIONS
  The LNR seems to be a more reliable prognostic factor than LNI for CRC lung metastasis. Prospective studies are necessary.
authors.affiliation: Department of Thoracic Surgery, Nouvel Hôpital Civil, 1, Strasbourg University Hospital, Strasbourg, France.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Renaud
authors.affiliation: Department of Thoracic Surgery, Nouvel Hôpital Civil, 1, Strasbourg University Hospital, Strasbourg, France pierre-emmanuel.falcoz@wanadoo.fr.
authors.forename: Pierre-Emmanuel
authors.initials: PE
authors.lastname: Falcoz
authors.affiliation: Department of Thoracic Surgery, Nouvel Hôpital Civil, 1, Strasbourg University Hospital, Strasbourg, France.
authors.forename: Anne
authors.initials: A
authors.lastname: Olland
authors.affiliation: Department of Biostatistics, Strasbourg University Hospital, Strasbourg, France.
authors.forename: Mickaël
authors.initials: M
authors.lastname: Schaeffer
authors.affiliation: Department of Thoracic Surgery, Nouvel Hôpital Civil, 1, Strasbourg University Hospital, Strasbourg, France.
authors.forename: Jérémie
authors.initials: J
authors.lastname: Reeb
authors.affiliation: Department of Thoracic Surgery, Nouvel Hôpital Civil, 1, Strasbourg University Hospital, Strasbourg, France.
authors.forename: Nicola
authors.initials: N
authors.lastname: Santelmo
authors.affiliation: Department of Thoracic Surgery, Nouvel Hôpital Civil, 1, Strasbourg University Hospital, Strasbourg, France.
authors.forename: Gilbert
authors.initials: G
authors.lastname: Massard
mesh_terms: D000368:Aged; D002277:Carcinoma / Q000401:mortality / Q000556:secondary* / Q000601:surgery*; D015179:Colorectal Neoplasms / Q000401:mortality / Q000473:pathology*; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008175:Lung Neoplasms / Q000401:mortality / Q000556:secondary* / Q000601:surgery*; D008197:Lymph Node Excision; D008198:Lymph Nodes / Q000473:pathology* / Q000601:surgery; D008207:Lymphatic Metastasis; D008297:Male; D059146:Metastasectomy / Q000009:adverse effects / Q000379:methods* / Q000401:mortality; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D011013:Pneumonectomy / Q000009:adverse effects / Q000401:mortality; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome
keywords: Colorectal metastases; Lung metastasectomy; Thoracic lymph nodes