title: [Smoking: a prognostic factor of lung cancer survival].
abstract: Eighty % of lung cancer cases are attributable to smoking. There have been several publications concerning the prognostic factor role of smoking in lung cancer survival. Our research proposed four aims: 1) to gather more concise data about the smoking habits of lung cancer patients; 2) to demonstrate the relationship between the quantitative indicator pack year index (PYI) of smoking history and survival; 3) to test the hypothesis that smoking is not only a risk factor, but also a prognostic factor in lung cancer survival; and 4) to assess the survival advantage of smoking cessation at the time of diagnosis among lung cancer patients. We employed a questionnaire based prospective cohort design of lung cancer patients diagnosed in Budapest, 2009. We collected data on the method of cancer detection, cell types, stage, treatment, comorbidities and smoking habits at baseline. Follow-up questionnaires were completed to document changes (survival, smoking habits) every six months. Our sample included 929 patients (521 males and 408 females). The majority had a history of smoking (79%), including 68% current and 32% former smokers. The average PYI was 33. Fifty-seven % of current smokers quit at the time of lung cancer diagnosis (3% relapsed) and 43% continued smoking. The 30-month survival probabilities were found to be as follows: smokers who had PYI≤39: 44%; PYI≥40: 35%. PYI ≤39 vs. ≥40 [HR=1.26, 95% CI 1.02 1.64; p=0.045]. The 30-month survival proved to be significantly better for those patients who quit at the time of diagnosis (quitters: 54% vs. continuous smokers: 42% [HR=1.29, 95% CI 1.12 1.78; p<0.001]). The benefit of quitting smoking was observed both in the surgically resected and the not resected group. Our results demonstrate that smoking is not only a risk factor for lung cancer, but also a strong prognostic factor of survival at 30 months after diagnosis. Survival is also significantly influenced by the smoking history (PYI). It is markedly important for smoking patients to quit smoking at the time of diagnosis.
authors.affiliation: Országos Korányi Tbc és Pulmonológiai Intézet, Budapest, Hungary. kovac@koranyi.hu
authors.forename: Gábor
authors.initials: G
authors.lastname: Kovács
authors.forename: Andrea
authors.initials: A
authors.lastname: Barsai
authors.forename: Mária
authors.initials: M
authors.lastname: Szilasi
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000209:etiology* / Q000401:mortality* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects*; D016540:Smoking Cessation; D011795:Surveys and Questionnaires