Smoking and prognosis in women with breast cancer.

The hypothesis was that smokers might have more aggressive types of breast cancer because of either delayed diagnosis or higher grade and hence have a worse prognosis. A cohort of breast cancer patients completed a lifestyle questionnaire at the time of diagnosis, including whether they were current smokers, ex-smokers or lifelong non-smokers. Ex-smokers were asked when they had stopped. The participants were 166 women with stage I/II invasive breast cancer diagnosed between October 1984 and March 1987. Participants were divided into three groups: current smokers, ex-smokers and non-smokers. Survival curves were produced by using Cox proportional hazards analysis, with outcome variables for overall and breast cancer-specific survival together with distant relapse-free survival. Smoking was the third most important predictor of distant relapse-free, breast cancer-specific and overall survival after stage and age at diagnosis. These results suggest that smokers are not only more likely to die of other diseases, but also have a higher mortality from breast cancer, compared with those with the disease who have never smoked. The best prognosis, however, was found in those who had given up smoking.