title: Colorectal cancer occurs earlier in those exposed to tobacco smoke: implications for screening.
abstract: BACKGROUND
  Colorectal cancer (CRC) is the third most common cancer in the USA. While various lifestyle factors have been shown to alter the risk for colorectal cancer, recommendations for the early detection of CRC are based only on age and family history.
  
  
  METHODS
  This case-only study examined the age at diagnosis of colorectal cancer in subjects exposed to tobacco smoke. Subjects included all patients who attended RPCI between 1957 and 1997, diagnosed with colorectal cancer, and completed an epidemiologic questionnaire. Adjusted linear regression models were calculated for the various smoking exposures.
  
  
  RESULTS
  Of the 3,540 cases of colorectal cancer, current smokers demonstrated the youngest age of CRC onset (never: 64.2 vs. current: 57.4, P < 0.001) compared to never smokers, followed by recent former smokers. Among never smokers, individuals with past second-hand smoke exposure were diagnosed at a significantly younger age compared to the unexposed.
  
  
  CONCLUSIONS
  This study found that individuals with heavy, long-term tobacco smoke exposure were significantly younger at the time of CRC diagnosis compared to lifelong never smokers. The implication of this finding is that screening for colorectal cancer, which is recommended to begin at age 50 years for persons at average risk should be initiated 5-10 years earlier for persons with a significant lifetime history of exposure to tobacco smoke.
authors.affiliation: Department of Radiation Oncology, University of Rochester, Rochester, NY 14642, USA. Luke_Peppone@urmc.rochester.edu
authors.forename: Luke J
authors.initials: LJ
authors.lastname: Peppone
authors.forename: Martin C
authors.initials: MC
authors.lastname: Mahoney
authors.forename: K Michael
authors.initials: KM
authors.lastname: Cummings
authors.forename: Arthur M
authors.initials: AM
authors.lastname: Michalek
authors.forename: Mary E
authors.initials: ME
authors.lastname: Reid
authors.forename: Kirsten B
authors.initials: KB
authors.lastname: Moysich
authors.forename: Andrew
authors.initials: A
authors.lastname: Hyland
mesh_terms: D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D015179:Colorectal Neoplasms / Q000453:epidemiology / Q000209:etiology*; D005260:Female; D006801:Humans; D008297:Male; D008403:Mass Screening / Q000379:methods*; D008875:Middle Aged; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects*; D016540:Smoking Cessation / Q000706:statistics & numerical data; D014028:Tobacco Smoke Pollution / Q000009:adverse effects*
chemical_list: D014028:Tobacco Smoke Pollution