CIGARETTE-SMOKING AND RISK OF FATAL BREAST-CANCER

The authors examined the association of fatal breast cancer and cigare tte smoking in a large, prospective mortality study of US adults. Afte r 6 years of follow-up, 880 cases of fatal breast cancer we re observe d in a cohort of 604,412 women who were cancer-free at interview in 19 82. Cox proportional hazards modeling, adjusted for other risk factors , found that current smoking was significantly related to fatal breast cancer risk (adjusted rate ratio (RR) = 1.26, 95% confidence interval (CI) 1.05-1.50). A negative association was observed for former smoke rs, but this was not statistically significant (RR = 0.85, 95% CI 0.70 -1.03). The association of current smoking with fatal breast cancer ri sk increased with increasing numbers of cigarettes per day and with to tal number of years smoked. For smokers of 40 or more cigarettes per d ay, the rate ratio was 1.74 (95% CI 1.15-2.62). The authors hypothesiz e that these results may be due to either a poorer prognosis among bre ast cancer cases who smoke or a delayed diagnosis among current smoker s who do not receive mammograms as often as never or former smokers. W omen who smoke should be targeted for breast cancer screening services .