title: The importance of the lepidic component as a prognostic factor in stage I pulmonary adenocarcinoma.
abstract: BACKGROUND
  Stage I pulmonary adenocarcinoma (PA) can offer an unfavorable prognosis. The aim of this study was to classify the prognosis of stage I PA on the basis of the lepidic component and to confirm whether the lepidic component can be used as a criterion for predicting the prognosis of stage I PA.
  
  
  METHODS
  We conducted a retrospective study of patients who underwent curative surgery for stage I and IIA PA. Stage I disease was divided into three groups on the basis of the lepidic component: group 1, ≤10%; group 2, >10 to 50%; and group 3, >50%. We compared recurrence-free survival (RFS) rates among groups 1, 2, and 3, and stage IIA disease. We also evaluated risk factors for disease recurrence with multivariate analysis.
  
  
  RESULTS
  A total of 224 patients were included in our study; most patients (n=201) had stage I disease. Three-year RFS rates in group 1 (n=73), group 2 (n=75), and group 3 (n=53) were 74.1, 90.4, and 90.0%, respectively. There was a significant difference in RFS between group 1 and group 2 (p=0.009). The 3-year RFS rate in stage IIA disease was 61.4%. There were no significant differences in RFS between group 1 and stage IIA disease (p=0.163). In multivariate analysis, group 1 had the highest risk of recurrence (HR 5.806, p=0.006) in stage I PA.
  
  
  CONCLUSIONS
  Stage I PA with a lepidic component≤10% was associated with an unfavorable prognosis that was similar to the prognosis of stage IIA disease. The prognosis for stage I PA should not be based on general criteria, but instead, the lepidic component should be evaluated and considered when determining disease prognosis.
authors.affiliation: Department of Thoracic & Cardiovascular Surgery, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, 222 Banpo-daero, Seocho-gu, Seoul, 06591, Republic of Korea.
authors.forename: Youngkyu
authors.initials: Y
authors.lastname: Moon
authors.affiliation: Department of Thoracic & Cardiovascular Surgery, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, 222 Banpo-daero, Seocho-gu, Seoul, 06591, Republic of Korea.
authors.forename: Sook Whan
authors.initials: SW
authors.lastname: Sung
authors.affiliation: Department of Hospital Pathology, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.
authors.forename: Kyo Young
authors.initials: KY
authors.lastname: Lee
authors.affiliation: Department of Internal Medicine, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.
authors.forename: Young Kyoon
authors.initials: YK
authors.lastname: Kim
authors.affiliation: Department of Thoracic & Cardiovascular Surgery, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, 222 Banpo-daero, Seocho-gu, Seoul, 06591, Republic of Korea. jaekpark@catholic.ac.kr.
authors.forename: Jae Kil
authors.initials: JK
authors.lastname: Park
mesh_terms: D000230:Adenocarcinoma / Q000473:pathology* / Q000601:surgery; D002288:Adenocarcinoma, Mucinous / Q000473:pathology* / Q000601:surgery; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018278:Carcinoma, Neuroendocrine / Q000473:pathology* / Q000601:surgery; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008175:Lung Neoplasms / Q000473:pathology* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009364:Neoplasm Recurrence, Local / Q000473:pathology* / Q000601:surgery; D009367:Neoplasm Staging; D011379:Prognosis; D012189:Retrospective Studies; D015996:Survival Rate