title: Invasive adenocarcinoma of the lung is associated with the upper lung regions.
abstract: OBJECTIVE
  We postulated that ventilation-perfusion (V/Q) relationships within the lung might influence where lung cancer occurs. To address this hypothesis we evaluated the location of lung adenocarcinoma, by both tumor lobe and superior-inferior regional distribution, and associated variables such as emphysema.
  
  
  METHODS
  One hundred fifty-nine cases of invasive adenocarcinoma and adenocarcinoma with lepidic features were visually evaluated to identify lobar or regional tumor location. Regions were determined by automated division of the lungs into three equal volumes: (upper region, middle region, or lower region). Automated densitometry was used to measure radiographic emphysema.
  
  
  RESULTS
  The majority of invasive adenocarcinomas occurred in the upper lobes (69%), with 94% of upper lobe adenocarcinomas occurring in the upper region of the lung. The distribution of adenocarcinoma, when classified as upper or lower lobe, was not different between invasive adenocarcinoma and adenocarcinoma with lepidic features (formerly bronchioloalveolar cell carcinoma, P = 0.08). Regional distribution of tumor was significantly different between invasive adenocarcinoma and adenocarcinoma with lepidic features (P = 0.001). Logistic regression analysis with the outcome of invasive adenocarcinoma histology was used to adjust for confounders. Tumor region continued to be a significant predictor (OR 8.5, P = 0.008, compared to lower region), whereas lobar location of tumor was not (P = 0.09). In stratified analysis, smoking was not associated with region of invasive adenocarcinoma occurrence (P = 0.089). There was no difference in total emphysema scores between invasive adenocarcinoma cases occurring in each of the three regions (P = 0.155). There was also no difference in the distribution of region of adenocarcinoma occurrence between quartiles of emphysema (P = 0.217).
  
  
  CONCLUSIONS
  Invasive adenocarcinoma of the lung is highly associated with the upper lung regions. This association is not related to smoking, history of COPD, or total emphysema. The regional distribution of invasive adenocarcinoma may be due to V/Q relationships or other local factors.
authors.affiliation: Division of Pulmonary and Critical Care, University of Vermont College of Medicine, 89 Beaumont Avenue, Burlington VT 05405, United States.
authors.forename: C Matthew
authors.initials: CM
authors.lastname: Kinsey
authors.affiliation: Department of Environmental Health and Epidemiology, Harvard School of Public Health, 665 Huntington Ave, Boston, MA 02115, United States; Department of Radiology, Brigham and Women's Hospital, 75 Francis Street, Boston, MA 02115, United States.
authors.forename: Raul San Jose
authors.initials: RS
authors.lastname: Estepar
authors.affiliation: Department of Epidemiology and Biostatistics, School of Public Health, Nanjing Medical University, Nanjing, Jiangsu, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: Department of Epidemiology and Biostatistics, School of Public Health, Southeast University, Nanjing, Jiangsu, China.
authors.forename: Xiaojin
authors.initials: X
authors.lastname: Yu
authors.affiliation: Department of Environmental Health and Epidemiology, Harvard School of Public Health, 665 Huntington Ave, Boston, MA 02115, United States.
authors.forename: Nancy
authors.initials: N
authors.lastname: Diao
authors.affiliation: Division of Hematology and Oncology, Massachusetts General Hospital, 55 Fruit Street, Boston, MA 02114, United States.
authors.forename: Rebecca Suk
authors.initials: RS
authors.lastname: Heist
authors.affiliation: Division of Thoracic Surgery, Massachusetts General Hospital, 55 Fruit Street, Boston, MA 02114, United States.
authors.forename: John C
authors.initials: JC
authors.lastname: Wain
authors.affiliation: Department of Pathology, Massachusetts General Hospital, 55 Fruit Street, Boston, MA 02114, United States.
authors.forename: Eugene J
authors.initials: EJ
authors.lastname: Mark
authors.affiliation: Pulmonary and Critical Care Medicine, Brigham and Women's Hospital, 75 Francis Street, Boston, MA 02115, United States.
authors.forename: George
authors.initials: G
authors.lastname: Washko
authors.affiliation: Pulmonary and Critical Care Unit, Massachusetts General Hospital, 55 Fruit Street, Boston, MA 02114, United States; Departments of Environmental Health and Epidemiology, Harvard School of Public Health, 665 Huntington Ave, Boston, MA 02115, United States. Electronic address: dchris@hsph.harvard.edu.
authors.forename: David C
authors.initials: DC
authors.lastname: Christiani
mesh_terms: D000230:Adenocarcinoma / Q000473:pathology*; D000077192:Adenocarcinoma of Lung; D000368:Aged; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008168:Lung / Q000473:pathology*; D008175:Lung Neoplasms / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009928:Organ Specificity; D011446:Prospective Studies; D011656:Pulmonary Emphysema / Q000175:diagnosis
keywords: Emphysema; Non-small cell lung cancer; Tumor location