Smoking increases risk of death of breast cancer patients



Association between active smoking and risk of death among breast cancer patients reported in previous studies has been inconsistent. We investigated the association between active and passive smoking and risk of all-cause and breast cancer-specific death among female breast cancer patients in relation to menopausal and tumor estrogen/progesterone receptor (ER/PR) status. This study included 848 patients admitted to a single hospital in Japan from 1997 to 2007. Active or passive smoking status was assessed using a self-administered questionnaire. The patients were followed until December 31, 2010. We used Cox proportional-hazard model to estimate hazard ratio (HR). During a median follow-up period of 6.7 years, 170 all-cause and 132 breast cancer-specific deaths were observed. Among premenopausal patients, current smokers showed a non-significant higher risk of all-cause and breast cancer-specific death. A duration of smoking >21.5 years was positively associated with all-cause (HR = 3.09, 95% confidence interval [CI], 1.17-8.20) and breast cancer-specific death (HR = 3.35, 95% CI: 1.22-9.23, Ptrend = 0.035) among premenopausal patients. In premenopausal patients with ER+ or PR+ tumor, there was some suggestion that a longer duration of smoking was associated with higher risk of all-cause and breast cancer-specific death. Passive smoking demonstrated no significant risk. Our results suggest that a longer duration of active smoking is associated with an increased risk of all-cause and breast cancer-specific death among premenopausal patients, possibly with hormonal receptor-positive tumors. Breast cancer patients should be informed about the importance of smoking cessation.

Whether or not a woman smokes may have a decisive impact on her breast cancer outcome. This is the case in the years preceding menopause, write Japanese researchers in “Cancer Science”.

Researchers from Tohoku University Graduate School of Medicine in Sendai analysed data from 848 women with breast cancer who were followed for an average of 6.7 years. Premenopausal women who had smoked for more than 21.5 years had a 3.1 times higher risk of dying from any cause and a 3.4 times higher risk of dying from breast cancer.

This effect was especially relevant in carcinomas that were both oestrogen and progesterone-positive. This association was not found in postmenopausal patients.

The results clearly demonstrate how strongly smoking may impact the outcome of the illness. “Hopefully this paper will serve to reduce the number of breast cancer patients who continue to smoke”, said co-author Yuko Minami.

Kakugawa, Y., Kawai, M., Nishino, Y., Fukamachi, K.,  et al. (2015). Smoking and survival after breast cancer diagnosis in Japanese women: A prospective cohort study. Cancer Science, Accepted Article’, doi: 10.1111/cas.12716.