title: Influence of type of cigarette on peripheral versus central lung cancer.
abstract: OBJECTIVE
  Adenocarcinoma has replaced squamous cell carcinoma as the most common cell type of lung cancer in the United States. It has been proposed that this shift is due to the increased use of filter and lower-tar cigarettes, resulting in increased delivery of smoke to peripheral regions of the lungs, where adenocarcinoma usually occurs. We reviewed radiologic data to evaluate the hypothesis that tumors in smokers of cigarettes with lower-tar yield are more likely to occur peripherally than tumors in smokers of higher-yield cigarettes.
  
  
  METHODS
  At two urban academic medical centers, we reviewed computed tomographic scans, chest radiographs, and medical records to assign tumor location (peripheral or central) for 330 smokers diagnosed with carcinoma of the lung between 1993 and 1999. We compared the proportion of tumors in a peripheral versus central location by lifetime filter use and average lifetime tar rating (< 21 and > or = 21 mg).
  
  
  RESULTS
  Tumor location (69% peripheral and 31% central) was unrelated to cigarette filter use. Smokers of cigarettes with lower-tar ratings were more likely than those with higher ratings to have peripheral rather than central tumors (odds ratio, 1.76; 95% confidence interval, 0.89-3.47). When restricted to subjects with adenocarcinoma or squamous cell carcinoma, the odds ratio (95% confidence interval) was 2.31 (1.05-5.08).
  
  
  CONCLUSIONS
  Among cigarette smokers with lung cancer, use of cigarettes with lower-tar yield was associated with preferential occurrence of tumors in peripheral sites. Our findings support the hypothesis that changes in smoking associated with lower-tar cigarettes have led to a shift in the location of smoking-related lung cancer.
authors.affiliation: Department of Epidemiology, Boston University School of Public Health, Boston, MA 02118, USA. danbrook@bu.edu
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Brooks
authors.forename: John H M
authors.initials: JH
authors.lastname: Austin
authors.forename: Robert T
authors.initials: RT
authors.lastname: Heelan
authors.forename: Michelle S
authors.initials: MS
authors.lastname: Ginsberg
authors.forename: Victor
authors.initials: V
authors.lastname: Shin
authors.forename: Sara H
authors.initials: SH
authors.lastname: Olson
authors.forename: Joshua E
authors.initials: JE
authors.lastname: Muscat
authors.forename: Steven D
authors.initials: SD
authors.lastname: Stellman
mesh_terms: D000368:Aged; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000209:etiology* / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D012907:Smoking / Q000009:adverse effects*; D013638:Tars / Q000009:adverse effects* / Q000145:classification; D014057:Tomography, X-Ray Computed
chemical_list: D013638:Tars