Smoking cessation prolongs survival in female cancer survivors - the Danish nurse cohort.

Abstract

To explore smoking cessation between cancer survivors and cancer-free women, and the potential survival benefits from smoking cessation in cancer surviving women. We pooled 46,334 responses from the Danish Nurse Cohort. The cohort consists of female nurses, who were invited for surveys in 1993, 1999 and 2009. Participants were linked to nationwide registries on hospitalization, cause of death and migration through 2016. Odds for smoking cessation by cancer diagnosis were computed in propensity score matched logistic regression models, while survival by postdiagnosis smoking cessation was estimated in cox proportional hazards models. Eligible for analysis were 7841 women (mean age=56.7 years, SD±7.2), who were smokers at baseline and survived to the next follow-up survey. Of these, 545 women were diagnosed with cancer and matched by propensity score (1:2) with 1090 cancer-free women. Odds for smoking cessation were significantly higher in cancer-diagnosed women compared to their cancer-free peers (OR=1.31, 95% CI: 1.06-1.61). Moreover, mortality risk was significantly lower among cancer survivors who stopped smoking (HR=0.64, 95% CI: 0.46-0.91), compared to persistent smokers. The results suggest considerable survival benefits from smoking cessation in cancer surviving female nurses, and that the time surrounding cancer diagnosis may serve as a teachable moment for smoking cessation. However, due to substantial methodological limitations embedded in the study, careful interpretation of the presented results is warranted. Future studies are needed to demonstrate the effects of diagnosis on smoking cessation as well as the effects of smoking cessation on survival in female cancer populations.