Lifetime history of tobacco consumption and K-ras mutations in exocrine pancreatic cancer.

Results: Mutated cases were nonsignificantly less likely to have been smokers than wild-type cases: the odds ratio adjusted by age and sex was 0.54 (95% confidence interval, 0.10Y2.69; P = 0.613). With respect to never smokers, adjusted odds ratios for former and current smokers were 0.79 and 0.36, respectively (P = 0.193). Packyears smoked, years of smoking, and cigarettes smoked per year also tended to be higher in nonmutated than in mutated cases. Neither age at onset of smoking nor the time between quitting and diagnosis were associated with K-ras.