Eligibility Criteria

As proposed by the PRISMA guidelines, we used the population, intervention, comparator, outcome, and study design approach to specify the inclusion criteria. Reports were considered relevant when they included patients who received a diagnosis of prostate cancer (population), recorded smoking status (comparator), and the patients underwent primary curative treatment (intervention) to independently determine the association of smoking status with BCR, metastasis, and CSM (outcome) using Cox proportional hazards regression or logistic regression analyses (study design). We were primarily focused on comparing the risk of current, former, and never smoking.

Second, we aimed to investigate cumulative risk groups (pack-years) and different durations of smoking cessation. The main focus regarding primary curative treatment was on RP, RT, or both. Studies with mixed treatment populations had to consist of at least 80% of these 2 modalities and had to be adjusted for primary therapy. Only studies with smoking status examined in multivariable Cox proportional hazards regression analyses were considered for meta-analysis. If more than 1 report of the same study population existed, we selected the most recent regarding a specific survival outcome. Review articles, editorials, comments, and meeting abstracts were excluded. Search results were independently screened by B.F. and C.P. The references of the included articles were scanned for additional studies of interest. Disagreements were resolved by consulting the senior author (S.F.S.).