A Systematic Review and Meta-analysis of Tobacco Use and Prostate Cancer Mortality and Incidence in Prospective Cohort Studies

Abstract

Context An association between tobacco smoking and prostate cancer (PCa) incidence and mortality was suggested in an earlier meta-analysis of 24 prospective studies in which dose–response associations and risks per unit of tobacco use were not examined. Objective We investigated the association between several measures of tobacco use and PCa mortality (primary outcome) and incidence (secondary outcome) including dose–response association. Evidence acquisition Relevant articles from prospective studies were identified by searching the PubMed and Web of Science databases (through January 21, 2014) and reference lists of relevant articles. Combined relative risks (RRs) and 95% confidence intervals (CIs) were calculated using random effects methods. We also calculated population attributable risk (PAR) for smoking and PCa mortality. Evidence synthesis We included 51 articles in this meta-analysis (11 823 PCa deaths, 50 349 incident cases, and 4 082 606 cohort participants). Current cigarette smoking was associated with an increased risk of PCa death (RR: 1.24; 95% CI, 1.18–1.31), with little evidence for heterogeneity and publication bias. The number of cigarettes smoked per day had a dose–response association with PCa mortality ( p = 0.02; RR for 20 cigarettes per day: 1.20). The PAR for cigarette smoking and PCa deaths in the United States and Europe were 6.7% and 9.5%, respectively, corresponding to >10 000 deaths/ year in these two regions. Current cigarette smoking was inversely associated with incident PCa (RR: 0.90; 95% CI, 0.85–0.96), with high heterogeneity in the results. However, in studies completed in 1995 or earlier (considered as completed before the prostate-specific antigen screening era), ever smoking showed a positive association with incident PCa (RR: 1.06; 95% CI, 1.00–1.12) with little heterogeneity. Conclusions Combined evidence from observational studies shows a modest but statistically significant association between cigarette smoking and fatal PCa. Smoking appears to be a modifiable risk factor for PCa death. Patient summary Smoking increases the chance of prostate cancer death. Not smoking prevents this harm and many other tobacco-related diseases.

Influence of lifestyle choices on risks of CYP1B1 polymorphisms for prostate cancer

“…For smokers, although only a near trend was observed as a risk for prostate cancer in this study ( P  = .109), meta‐analysis shows a significant correlation for current smoking 6. A possible reason for the meagre significance may be due to the lack of information regarding the amount of smoking per individual and perhaps a breakdown by pack‐years may show a significant risk among heavy smokers, as a dose‐response effect of smoking was observed for prostate cancer mortality 6. Tobacco smoke contains numerous compounds that can promote cancer and agents such as polycyclic aromatic hydrocarbons (PAH) have been shown to enhance cancer of the lung, bladder, and head and neck 12.…”

“…Studies demonstrate acetaldehyde to affect cellular properties such as DNA synthesis and repair,24 cause DNA mutations and adducts24, 25 and undergo further metabolism to form reactive radicals that can bind DNA 26. For smokers, although only a near trend was observed as a risk for prostate cancer in this study ( P  = .109), meta‐analysis shows a significant correlation for current smoking 6. A possible reason for the meagre significance may be due to the lack of information regarding the amount of smoking per individual and perhaps a breakdown by pack‐years may show a significant risk among heavy smokers, as a dose‐response effect of smoking was observed for prostate cancer mortality 6.…”

“…In the USA in the year 2010, the estimated death rate of all cancers due to cigarette smoking was roughly 38% with about 112 000 deaths among men aged 35 years or older and does not include additional deaths from environmental tobacco smoke or usage of cigars, pipes or smokeless tobacco 5. In prostate, a meta‐analysis of 4 million cohort participants showed that current cigarette smoking was correlated with increased risk of cancer death (relative risk [RR]; 1.24, 95% confidence interval [CI]; 1.18–1.31) with cigarettes smoked per day having a dose‐response association with cancer mortality 6. Also, compared with non‐smokers, former smokers (hazard ratio [HR]; 1.63, 95% CI; 1.30–2.04, P  < .001) and current smokers (HR; 1.80, 95% CI 1.45–2.24, P  < .001) had a higher risk of prostate cancer biochemical recurrence 7…”

Smoking Is Associated with Acute and Chronic Prostatic Inflammation: Results from the REDUCE Study

“…Cigarette smoking has been associated with higher prostate cancer mortality in all comers and more disease recurrence, metastasis, and cancer-specific mortality after surgery and radiotherapy for prostate cancer (1)(2)(3)(4)(5). Although, the pathways by which smoking affects prostate carcinogenesis and prostate cancer progression are largely unknown, several potential mechanisms have been proposed, including genetic and epigenetic changes, enhanced angiogenesis, life style factors, and inflammation.…”

Heritability of prostate cancer: a tale of rare variants and common single nucleotide polymorphisms

“…The two most significant cancer risk factors, smoking and obesity, do not appear to be strong risk factors for PCa. A recent systematic review and meta-analysis summarized the current literature of tobacco use and PCa mortality and incidence (1). This meta-analysis included 51 cohort studies (50,349 incident cases and 4,082,606 cohort participants) and found a dichotomized association between smoking and PCa risk.…”