title: Tumor invasion of extralobar soft tissue beyond the hilar region does not affect the prognosis of surgically resected lung cancer patients.
abstract: BACKGROUND
  Visceral pleural invasion, which is defined as tumor extension beyond the elastic lamina, is one of the most important prognostic factors in patients who have undergone curative resection for non-small cell lung cancer. However, in pathologic slides, pleural elastic lamina could not be found in the hilar region in which the pleura is reflected. Till date, when cancer cells are seen in this region, a basical agreement dealing with T factor is controversial among pathologists. The purpose of this study is to evaluate the significance of tumor invasion of that region as a prognostic factor.
  
  
  METHODS
  We reviewed 91 cases of surgically resected lung cancer in which invasion of the hilar region was visible macroscopically. By microscopic examination, we divided them into three groups: a group in which no cancer cells are seen in the soft tissue beyond the hilar region (group A), a group in which cancer cells are seen in the soft tissue beyond the hilar region (group B), and a group in which cancer cells could not be seen in the soft tissue beyond the hilar region but invade into the mediastinal visceral pleura at some other site (group C). We then evaluated the clinicopathologic characteristics of the patients and their outcome.
  
  
  RESULTS
  There was no statistically significant difference in the 5-year overall survival rate or disease-free survival rate between group A and group B (overall: 55 versus 48%; disease free: 43 versus 42%), but disease-free survival of group C was significantly lesser than that of group A and group B (A versus C: p = 0.022; B versus C: p = 0.040).
  
  
  CONCLUSIONS
  Tumor invasion of the soft tissue beyond hilar region would not be a prognostic factor in patients who have undergone curative resection for primary lung cancer, although investigation of larger number of cases will be needed to confirm the validity of our conclusion.
authors.affiliation: Division of Pathology, Research Center for Innovative Oncology, National Cancer Center Hospital East, Kashiwa, Chiba, Japan.
authors.forename: Hajime
authors.initials: H
authors.lastname: Otsuka
authors.forename: Genichiro
authors.initials: G
authors.lastname: Ishii
authors.forename: Junji
authors.initials: J
authors.lastname: Yoshida
authors.forename: Yoko
authors.initials: Y
authors.lastname: Yamaguchi
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Hishida
authors.forename: Mitsuyo
authors.initials: M
authors.lastname: Nishimura
authors.forename: Kanji
authors.initials: K
authors.lastname: Nagai
authors.forename: Atsushi
authors.initials: A
authors.lastname: Ochiai
mesh_terms: D000230:Adenocarcinoma / Q000401:mortality / Q000473:pathology* / Q000601:surgery; D000328:Adult; D000368:Aged; D018287:Carcinoma, Large Cell / Q000401:mortality / Q000473:pathology* / Q000601:surgery; D018278:Carcinoma, Neuroendocrine / Q000401:mortality / Q000473:pathology* / Q000601:surgery; D002289:Carcinoma, Non-Small-Cell Lung / Q000401:mortality / Q000473:pathology* / Q000601:surgery; 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; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D011379:Prognosis; D015996:Survival Rate