Association of cigarette smoking with interval to biochemical recurrence after radical prostatectomy: Results from the SEARCH database

Objectives: To analyze the association between cigarette smoking and biochemical recurrence (BCR) after radical prostatectomy among men from the Shared Equal Access Regional Cancer Hospital (SEARCH) cohort. Methods: We performed a retrospective analysis of 1267 subjects from the SEARCH cohort treated from 1998 to 2008 with smoking status available from the preoperative notes. A comparison of the baseline patient and disease characteristics between the current smokers and nonsmokers (past and never smokers combined) was performed using the chi-square and rank sum tests. The univariate and multivariate associations between smoking status and BCR-free survival were analyzed using Kaplan-Meier plots, the log-rank test, and Cox proportional hazard models. Results: Of the 1267 patients, 408 (32%) were active smokers and 859 (68%) were nonsmokers at surgery. The current smokers were younger (P <.001), more likely to be black (P <.001), and had a lower body mass index (P <.001), a greater percentage of positive biopsy cores (P = .039), a greater preoperative prostate-specific antigen level (P = .003), more extracapsular extension (P = .003) and seminal vesicle invasion (P = .029), and lower prostate volumes (P = .002). On univariate analysis, smokers had a risk of BCR similar to that of nonsmokers (hazard ratio 1.19, P = .129). On multivariate analysis, smoking was associated with an increased risk of BCR when adjusted for body mass index only (hazard ratio 1.37, P = .008). However, after adjustment for multiple preoperative characteristics, the association was attenuated and no longer statistically significant (hazard ratio 1.12, P = .325). After additional adjustment for postoperative features, such as tumor grade and stage, smoking was unrelated to the risk of BCR (hazard ratio 0.91, P = .502). Conclusions: Among patients undergoing radical prostatectomy in the SEARCH cohort, cigarette smoking was associated with slightly more advanced disease but a similar risk of BCR.