title: Excellent prognosis of lepidic-predominant lung adenocarcinoma: low incidence of lymphatic vessel invasion as a key factor.
abstract: OBJECTIVE
  To clarify the prognostic value of predominant histological subtypes for small-sized lung adenocarcinoma.
  
  
  METHODS
  Sixty-four specimens of resected invasive lung adenocarcinoma less than 20 mm in diameter with no lymph node metastasis were studied. These specimens were microscopically classified into predominant histological subtypes (21 lepidic, 16 acinar, 24 papillary, and three solid) according to the International association for the study of lung cancer/American thoracic society/European respiratory society adenocarcinoma classification. The relationships between tumor relapse and predominant histological subtypes were statistically analyzed. In addition the relationships between several pathological factors and predominant histological subtypes were statistically assessed.
  
  
  RESULTS
  Kaplan-Meier relapse-free curves showed a five-year relapse-free rate of 100% in 64 patients with lepidic-predominant adenocarcinoma, compared with a rate of 73.7% (p=0.035 by log rank test) in patients with non-lepidic-predominant adenocarcinoma (papillary, acinar, and solid). The only statistically significant pathological factor between lepidic-predominant and non-lepidic-predominant histological subtypes was lymphatic vessel invasion as assessed by logistic regression analysis.
  
  
  CONCLUSIONS
  In small-sized lung adenocarcinoma, lepidic-predominant histological subtype is the best prognostic factor, and a low incidence of lymphatic vessel invasion in the histological subtype is a key factor for an excellent prognosis.
authors.affiliation: Division of General Thoracic Surgery, Department of Surgery, Faculty of Medicine, Tottori University, Yonago, Japan arakik@med.tottori-u.ac.jp.
authors.forename: Kunio
authors.initials: K
authors.lastname: Araki
authors.affiliation: Division of General Thoracic Surgery, Department of Surgery, Faculty of Medicine, Tottori University, Yonago, Japan.
authors.forename: Yoshiteru
authors.initials: Y
authors.lastname: Kidokoro
authors.affiliation: Division of General Thoracic Surgery, Department of Surgery, Faculty of Medicine, Tottori University, Yonago, Japan.
authors.forename: Keiko
authors.initials: K
authors.lastname: Hosoya
authors.affiliation: Division of General Thoracic Surgery, Department of Surgery, Faculty of Medicine, Tottori University, Yonago, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Wakahara
authors.affiliation: Division of General Thoracic Surgery, Department of Surgery, Faculty of Medicine, Tottori University, Yonago, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Matsuoka
authors.affiliation: Division of General Thoracic Surgery, Department of Surgery, Faculty of Medicine, Tottori University, Yonago, Japan.
authors.forename: Yuzo
authors.initials: Y
authors.lastname: Takagi
authors.affiliation: Division of General Thoracic Surgery, Department of Surgery, Faculty of Medicine, Tottori University, Yonago, Japan.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Haruki
authors.affiliation: Division of General Thoracic Surgery, Department of Surgery, Faculty of Medicine, Tottori University, Yonago, Japan.
authors.forename: Ken
authors.initials: K
authors.lastname: Miwa
authors.affiliation: Division of General Thoracic Surgery, Department of Surgery, Faculty of Medicine, Tottori University, Yonago, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Taniguchi
authors.affiliation: Department of Pathology, Tottori University Hospital, Yonago, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Horie
authors.affiliation: Division of General Thoracic Surgery, Department of Surgery, Faculty of Medicine, Tottori University, Yonago, Japan.
authors.forename: Hiroshige
authors.initials: H
authors.lastname: Nakamura
mesh_terms: D002288:Adenocarcinoma, Mucinous / Q000453:epidemiology / Q000401:mortality / Q000556:secondary*; D000231:Adenocarcinoma, Papillary / Q000453:epidemiology / Q000401:mortality / Q000556:secondary*; D018267:Carcinoma, Acinar Cell / Q000453:epidemiology / Q000401:mortality / Q000556:secondary*; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D007564:Japan / Q000453:epidemiology; D008175:Lung Neoplasms / Q000453:epidemiology / Q000401:mortality / Q000473:pathology*; D008207:Lymphatic Metastasis; D042601:Lymphatic Vessels / Q000473:pathology*; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D011379:Prognosis; D015996:Survival Rate
keywords: Prognostic factor; histological subtype; lepidic-predominant; lymphatic vessel invasion; small lung adenocarcinoma