title: Longitudinal study of smoking patterns in relation to the development of smoking-related secondary primary tumors in patients with upper aerodigestive tract malignancies.
abstract: BACKGROUND
  The authors set out to assess the correlation between smoking-related second primary tumor (SPT) development and cigarette smoking habits after diagnosis and definitive treatment in patients with early-stage head and neck squamous cell carcinoma who were enrolled in a placebo-controlled randomized chemoprevention trial of 13-cis-retinoic acid.
  
  
  METHODS
  Longitudinal data collected for 10 years after the index diagnosis are presented for 1190 patients. Cox proportional hazards regression models were used to examine the effects of changes in smoking behavior on smoking-related SPT development.
  
  
  RESULTS
  One-third of all patients who quit smoking within 12 months before randomization experienced recurrence, compared with 6.9% and 10.4% of all never-smokers and former smokers, respectively. Approximately 16% of all current smokers stopped smoking, and nearly 22% of current smokers developed SPTs, compared with 14.5%, 13.2%, and 8.8% of all recent smokers, former smokers, and never-smokers, respectively. The probability of developing a smoking-related SPT was highest among patients who were current smokers at randomization. These patients, regardless of whether they ceased smoking during follow-up, were nearly three times more likely than patients who had never smoked to develop a smoking-related SPT. In contrast, former smokers and recent quitters who continued to abstain from smoking during follow-up were approximately 1.5 times more likely to develop an SPT compared with patients who had never smoked.
  
  
  CONCLUSIONS
  Patients who continue to smoke after the successful treatment of their index head and neck malignancies have a substantially higher risk of developing smoking-related SPTs.
authors.affiliation: Department of Biostatistics, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030-4009, USA. kim@mdanderson.org
authors.forename: Kim-Anh
authors.initials: KA
authors.lastname: Do
authors.forename: Marcella M
authors.initials: MM
authors.lastname: Johnson
authors.forename: J Jack
authors.initials: JJ
authors.lastname: Lee
authors.forename: Xi Feng
authors.initials: XF
authors.lastname: Wu
authors.forename: Qiong
authors.initials: Q
authors.lastname: Dong
authors.forename: Waun K
authors.initials: WK
authors.lastname: Hong
authors.forename: Fadlo R
authors.initials: FR
authors.lastname: Khuri
authors.forename: Margaret R
authors.initials: MR
authors.lastname: Spitz
mesh_terms: D005500:Follow-Up Studies; D006258:Head and Neck Neoplasms / Q000628:therapy; D006801:Humans; D008137:Longitudinal Studies; D016609:Neoplasms, Second Primary / Q000453:epidemiology*; D018307:Neoplasms, Squamous Cell / Q000628:therapy; D016016:Proportional Hazards Models; D016032:Randomized Controlled Trials as Topic; D012306:Risk; D012907:Smoking / Q000009:adverse effects*; D016540:Smoking Cessation; D013997:Time Factors