Background: While a number of studies indicating tobacco smoking has a detrimental impact on survival and recurrence after a prostate cancer diagnosis, there has been no quantitative review of this literature and it is unclear whether tobacco smoking affects clinical populations differentially. We conducted a systematic review and meta-analysis to investigate the associations between tobacco smoking and overall (OM) and prostate cancer-specific (PSM) mortality and recurrence after a prostate cancer diagnosis.
Methods: EMBASE and ISI Web of Science were searched for English-language studies, published up to August 17, 2017, which conducted a survival analysis to estimate the association between tobacco smoking and OM, PSM and/or recurrence. A random-effects meta-analysis was conducted to estimate the summary hazard ratios (HRs) for the associations between tobacco smoking and the three outcomes.
Results: A total of 28 studies met the inclusion criteria. The results of the primary meta-analysis indicate current smokers have significantly poorer overall survival (Summary HR=1.96, 95% CI=1.69, 2.28), prostate cancer-specific survival (Summary HR=1.79, 95%CI=1.47, 2.20) and recurrence-free survival (Summary HR =1.48, 95%CI=1.28, 1.72) than never smokers. Similar results were found in population-based studies and in studies conducted in specific clinical populations.
Conclusions: The results of this systematic review and meta-analysis indicate that tobacco smoking at prostate cancer diagnosis is associated with a significantly increased risk of overall mortality, prostate-cancer specific mortality and recurrence. Further research should concentrate on the impact of smoking cessation post-diagnosis and post-treatment on prognosis, and the feasibility and effectiveness of smoking cessation programs.