title: Micrometastasis to lymph nodes in stage I left lung cancer patients.
abstract: BACKGROUND
  To evaluate the frequency and clinicopathological characteristics of lymph node micrometastasis in left lung cancer patients diagnosed to be stage IA and IB based on routine histopathologic examinations, we examined the lymph nodes in patients who had undergone an extended mediastinal lymphadenectomy, using immunohistochemical methods.
  
  
  METHODS
  Paraffin-embedded tissue sections from the lymph nodes in 49 patients with stage I left lung cancers were studied. We used AE1/AE3 as the anticytokeratin and Ber-EP4 as the antiepithelial cell antibodies when performing immunohistochemical staining.
  
  
  RESULTS
  We identified micrometastasis of the lymph nodes in 13 (26.5%) of 49 patients with stage I left lung cancer. NO disease was reclassified as N1 disease in 5 cases, N2 disease in 6 cases, and N3 disease in 2 cases. The location of the micrometastatic lymph nodes proved to be wide regions including the contralateral and highest mediastinal nodes, and 6 (46.2%) out of the 13 patients with micrometastasis were thus presumed not to be completely eliminated by a standard lymphadenectomy through an ipsilateral thoracotomy. The five year survival rate of patients with reclassified N1 to N3 disease was 74%, and the presence of micrometastasis was found to have no significant effect on the outcomes.
  
  
  CONCLUSIONS
  The micrometastatic involvement of the lymph nodes was both more frequent and extensive than expected even in stage I left lung cancer. These results suggest that an extended mediastinal lymphadenectomy may therefore be required for the locoregional control of stage I left lung cancer patients.
authors.affiliation: Surgical Department of Respiratory Center, Mitsui Memorial Hospital, Tokyo, Japan. 2ryo@msc.biglobe.ne.jp
authors.forename: Ryoji
authors.initials: R
authors.lastname: Kawano
authors.forename: Enjo
authors.initials: E
authors.lastname: Hata
authors.forename: Shingo
authors.initials: S
authors.lastname: Ikeda
authors.forename: Hirozo
authors.initials: H
authors.lastname: Sakaguchi
mesh_terms: D000230:Adenocarcinoma / Q000473:pathology* / Q000601:surgery; D000368:Aged; D002294:Carcinoma, Squamous Cell / Q000401:mortality / Q000473:pathology* / Q000601:surgery; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008175:Lung Neoplasms / Q000401:mortality / Q000473:pathology* / Q000601:surgery; D008197:Lymph Node Excision; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011013:Pneumonectomy; D015996:Survival Rate