title: Comparisons of the clinicopathological features and survival outcomes between lung cancer patients with adenocarcinoma and squamous cell carcinoma.
abstract: OBJECTIVE
  Patients with lung cancer should be treated according to histological subtype because of the disparities in tumor aggressiveness and treatment responses. It is important to re-evaluate the clinicopathological features of the two major subtypes of lung cancer, adenocarcinoma (AD) and squamous cell carcinoma (SQ).
  
  
  METHODS
  We retrospectively analyzed data on the clinicopathological features and outcomes of 2059 patients with pulmonary AD and pulmonary SQ who had undergone complete resection at Nagoya University Hospital and Aichi Cancer Center between 1995 and 2012.
  
  
  RESULTS
  The cohort consisted of 1587 patients with AD (77 %) and 472 with SQ (23 %). Female gender, no history of smoking, and small tumor size were distinct characteristics of AD patients, and a higher age was a characteristic of SQ patients (p < 0.0001). A significant difference was observed in overall survival, with 5-year survival rates of 78 % in AD patients and 63 % in SQ patients. Patients with stage IA and IB SQ had significantly worse outcomes than patients with AD at the same stage (p < 0.0001). Because no survival difference was observed between SQ patients with stage IA, IB, and IIA tumors (p = 0.75), these patients were considered to have proposed stage IIA disease. Then, comparable survival curves were obtained between stages II and IIIA SQ and AD.
  
  
  CONCLUSIONS
  Patients with stage I SQ had significantly worse outcomes than patients with stage I AD. A newly defined stage grouping for SQ patients provided outcomes comparable to those of AD patients.
authors.affiliation: Department of Thoracic Surgery, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, 466-8550, Japan, tfukui@med.nagoya-u.ac.jp.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Fukui
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Taniguchi
authors.forename: Koji
authors.initials: K
authors.lastname: Kawaguchi
authors.forename: Koichi
authors.initials: K
authors.lastname: Fukumoto
authors.forename: Shota
authors.initials: S
authors.lastname: Nakamura
authors.forename: Yukinori
authors.initials: Y
authors.lastname: Sakao
authors.forename: Kohei
authors.initials: K
authors.lastname: Yokoi
mesh_terms: D000230:Adenocarcinoma / Q000401:mortality / Q000473:pathology* / Q000601:surgery; D000077192:Adenocarcinoma of Lung; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002294:Carcinoma, Squamous Cell / Q000401:mortality / Q000473:pathology* / Q000601:surgery; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000401:mortality / Q000473:pathology* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012189:Retrospective Studies; D012907:Smoking / Q000401:mortality / Q000473:pathology; D015996:Survival Rate