Cigarette smoking associated with colorectal cancer survival: a nationwide, population-based cohort study

Abstract

BACKGROUND AND AIM: The association between cigarette smoking and survival in patients with colorectal cancer (CRC) is inconsistent. Thus, we aim to investigate whether cigarette smoking is associated with the overall survival rates of CRC patients using a nationwide population-based cohort study in Taiwan. METHODS: Taiwan Cancer Registry and Taiwan’s national health insurance research database were used to identify CRC patients from 2011 to 2017. All patients were censored to date of death or the end of 2017. Tobacco use was evaluated by smoking status, duration, and amount of cigarette smoking before cancer diagnosis. Survival was estimated using Kaplan-Meier analysis and Cox regression was used to investigate the effect of smoking on overall survival (OS). RESULTS:A total of 49,837 CRC patients were included for analysis. The Kaplan–Meier survival analysis illustrated smoking to be significant association with OS in CRC patients (log-rank p=0.0123). The multivariable Cox model showed that CRC patients with ever smoking habit had 1.11-fold mortality risk (HR=1.11, 95% CI=1.05-1.16; p.0001) compared with CRC patients whom never smoking. This increased risk was also present in CRC patients who smoking cigarettes 20 per day (HR=1.13; 95% CI=1.02-1.25; p=0.0149) or smoking year of 11-30 years (HR=1.15; 95% CI=1.06-1.24; p=0.0004). Furthermore, stratified analysis of sex and tumour location showed the impact of smoking was higher in male CRC patients or cancer developed in rectum. CONCLUSIONS:Our results indicate that cigarette smoking significantly associates with worse survival in CRC patients. An integrated smoking cessation campaign is warranted to prevent the CRC mortality. KEYWORDS: Colorectal cancer, Cigarette smoking, Survival