title: Correlation between the number of lymph node metastases and lung metastasis in papillary thyroid cancer.
abstract: BACKGROUND
  A prognostic classification system based on aggregate numbers of lymph node metastases may better estimate the risk of distant metastasis.
  
  
  OBJECTIVE
  This investigation sought to evaluate a papillary thyroid cancer (PTC) patient's risk of distant metastasis.
  
  
  METHODS
  This was a retrospective analysis.
  
  
  METHODS
  The setting was a tertiary referral center.
  
  
  METHODS
  Included were 972 PTC patients.
  
  
  METHODS
  The intervention was compartment-oriented surgery.
  
  
  METHODS
  The main outcome measure was lung, bone, and liver metastasis.
  
  
  RESULTS
  Eighty-seven (9.0%) of the 972 PTC patients had distant metastases to lung (79 patients), bone (16 patients), liver (two patients), brain and skin (one patient each). For distant metastasis, more than 20 lymph node metastases had a specificity of 90.8% and a negative predictive value of 92.7%, whereas sensitivity and positive predictive value were low (27.6 and 22.9%). On multivariate logistic regression, 1-5, 6-10, and 11-20 involved nodes denoted a moderate risk of lung metastasis [odds ratio (OR), 9.9, 10.6, and 13.8; P ≤ 0.004], whereas more than 20 involved nodes indicated a high risk of lung metastasis (OR, 25.0; P < 0.001). Mediastinal lymph node metastasis carried a moderate risk of lung metastasis (OR, 7.5; P = 0.001). When these numeric categories of lymph node metastases were exchanged for current tumor node metastasis (TNM) N categories, the OR decreased from 25.0 (for > 20 lymph node metastases) to 16.4 (N1b), and from 9.9-13.8 (for 1-20 lymph node metastases) to 4.7 (N1a).
  
  
  CONCLUSIONS
  In PTC, categories of 0, 1-20, and more than 20 lymph node metastases correlate better with lung metastasis than current TNM N categories N0, N1a, and N1b.
authors.affiliation: Department of General, Visceral, and Vascular Surgery, Martin Luther University Halle-Wittenberg, Ernst-Grube-Strasse 40, D-06097 Halle (Saale), Germany. AndreasMachens@aol.com
authors.forename: Andreas
authors.initials: A
authors.lastname: Machens
authors.forename: Henning
authors.initials: H
authors.lastname: Dralle
mesh_terms: D000328:Adult; D000368:Aged; D002277:Carcinoma / Q000175:diagnosis / Q000473:pathology / Q000556:secondary* / Q000601:surgery; D002291:Carcinoma, Papillary; D002452:Cell Count; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000175:diagnosis / Q000556:secondary* / Q000601:surgery; D008197:Lymph Node Excision / Q000379:methods; D008198:Lymph Nodes / Q000473:pathology* / Q000601:surgery; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012189:Retrospective Studies; D000077273:Thyroid Cancer, Papillary; D013964:Thyroid Neoplasms / Q000175:diagnosis / Q000473:pathology* / Q000601:surgery; D013965:Thyroidectomy