title: Predictive factors of lymph node status in small peripheral non-small cell lung cancers: tumor histology is more reliable.
abstract: BACKGROUND
  During the past two decades, many studies have sought to find reliable predictors of N0 status in small-sized lung cancers. However, the way of tumor size measurement was usually not clearly stated, and controversy remains as to whether systematic lymph node dissection should be performed in patients with subcentimeter tumors.
  
  
  METHODS
  We reviewed correlations between lymph node involvement and clinicopathological variables in 243 small peripheral non-small cell lung cancers with their size measured in fresh specimens before formalin fixation. Histologic subtypes of adenocarcinomas were classified in line with the new International Association for the Study of Lung Cancer (IASLC)/American Thoracic Society (ATS)/European Respiratory Society (ERS) lung adenocarcinoma classification.
  
  
  RESULTS
  Incidence of N1 and N2 nodal involvement was 5.3 and 6.6 %, respectively. N2 disease was present in a proportion of subcentimeter tumors (2/53, 3.8 %). No lymph node metastasis was revealed in squamous cell carcinomas, adenocarcinoma in situ, minimally invasive adenocarcinoma, lepidic predominant adenocarcinoma, or invasive mucinous adenocarcinoma. Collectively, the five cell types accounted for 34.6 % of all the small peripheral cases.
  
  
  CONCLUSIONS
  Precise measurement of tumor size in fresh tissues revealed that tumor size was not a reliable predictor of N0 status. However, through histologic classification, systematic lymph node dissection might be avoided in more than one third of small peripheral NSCLC.
authors.affiliation: Department of Thoracic Surgery, Fudan University Shanghai Cancer Center, Shanghai, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Zhang
authors.forename: Yihua
authors.initials: Y
authors.lastname: Sun
authors.forename: Lei
authors.initials: L
authors.lastname: Shen
authors.forename: Yuan
authors.initials: Y
authors.lastname: Li
authors.forename: Jiaqing
authors.initials: J
authors.lastname: Xiang
authors.forename: Yawei
authors.initials: Y
authors.lastname: Zhang
authors.forename: Hong
authors.initials: H
authors.lastname: Hu
authors.forename: Haiquan
authors.initials: H
authors.lastname: Chen
mesh_terms: D000230:Adenocarcinoma / Q000473:pathology / Q000556:secondary* / Q000601:surgery; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002289:Carcinoma, Non-Small-Cell Lung / Q000473:pathology* / Q000556:secondary* / Q000601:surgery; D002294:Carcinoma, Squamous Cell / Q000556:secondary* / Q000601:surgery; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000473:pathology* / Q000601:surgery; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D012189:Retrospective Studies; D047368:Tumor Burden; D055815:Young Adult