title: Evaluation of the new IASLC/ATS/ERS proposed classification of adenocarcinoma based on lepidic pattern in patients with pathological stage IA pulmonary adenocarcinoma.
abstract: BACKGROUND
  The International association for the study of cancer (IASLC)/American thoracic society (ATS)/European respiratory society (ERS) has established a new subclassification of lung adenocarcinoma, especially for the lepidic pattern component, formerly called bronchioloalveolar adenocarcinoma (BAC). According to the new classification, BAC has been classified into the following 4 main subtypes: adenocarcinoma in situ (AIS), minimally invasive adenocarcinoma (MIA), invasive adenocarcinoma (IA), and variants of invasive adenocarcinoma (VIA). An observational study was conducted to validate this classification in patients with pathological stage IA pulmonary adenocarcinoma.
  
  
  METHODS
  147 patients treated for pathological stage IA lung adenocarcinoma by complete resection at Osaka University Medical Hospital from January 1993 to December 2002 were assessed. The tumor specimens of the cohort were classified into the 4 subgroups. In addition, these groups were compared for various prognostic factors.
  
  
  RESULTS
  Adenocarcinoma in situ was observed in 30 patients, MIA in 8, IA in 104, and VIA in 5 patients, with 5-year survival rates of 100, 100, 85.5, and 60.0 %, respectively. The relationship between the histological classification and K-ras mutation was significant (p < 0.001), especially when comparing the VIA group with the others (p ≪ 0.001). Ki67-labeling indices were significantly different between the AIS and IA groups (p = 0.040).
  
  
  CONCLUSIONS
  This study validated the proposed IASLC/ATS/ERS classification for pulmonary adenocarcinoma in patients with pathological stage IA pulmonary adenocarcinoma. The difference between AIS and IA may depend on the proliferation of the carcinoma. In addition, the difference between VIA and the other adenocarcinoma types may depend on genetic factors, especially K-ras mutations.
authors.affiliation: Department of General Thoracic Surgery, Osaka University Graduate School of Medicine, 2-2 (L5), Yamadaoka, Suita, Osaka, 565-0871, Japan, gilly64@thoracic.med.osaka-u.ac.jp.
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Nakagiri
authors.forename: Noriyoshi
authors.initials: N
authors.lastname: Sawabata
authors.forename: Eiichi
authors.initials: E
authors.lastname: Morii
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Inoue
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Shintani
authors.forename: Soichiro
authors.initials: S
authors.lastname: Funaki
authors.forename: Meinoshin
authors.initials: M
authors.lastname: Okumura
mesh_terms: D000230:Adenocarcinoma / Q000145:classification* / Q000235:genetics / Q000473:pathology; D065311:Adenocarcinoma in Situ / Q000145:classification / Q000235:genetics / Q000473:pathology; D000077192:Adenocarcinoma of Lung; D002282:Adenocarcinoma, Bronchiolo-Alveolar / Q000145:classification* / Q000235:genetics / Q000473:pathology; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D011905:Genes, ras / Q000235:genetics; D006801:Humans; D019394:Ki-67 Antigen / Q000378:metabolism; D008175:Lung Neoplasms / Q000145:classification* / Q000235:genetics / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009154:Mutation; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D015996:Survival Rate
chemical_list: D019394:Ki-67 Antigen