Impact of Smoking Intensity on Outcomes of Patients with Non Muscle Invasive Bladder Cancer Treated by BCG Immunotherapy

Background: Cigarette smoking is a well-known risk factor of bladder carcinogenesis. The clinical impact of smoking on bladder cancer recurrence and response to BCG immunotherapy remains unclear. We sought to investigate the effect of smoking intensity on bladder cancer response to BCG therapy, and the interactions between smoking and clinicopathological factors on bladder cancer recurrence. Methods: Clinical information was obtained from 81 smokers patients (smokers at diagnosis) with NMIBC treated with transurethral resection of the bladder tumor followed by BCG immunotherapy. The distribution of smoking intensity on patient age (>= 60 years or <60 years), gender, tumor grade, tumor stage, carcinoma in situ, multiplicity and tumor size was assessed. The effect of cigarette smoking on cancer recurrence was estimated using Cox proportional hazard models and Kaplan-Meier analysis. Results: The results showed that smoking intensity was significantly associated with response to BCG immunotherapy (p = 0.010). Univariate Cox regression analysis of clinicopathologic characteristics showed that PT1 stage, tumor size more than 3 cm and smoking intensity significantly increased the risk of recurrence (respectively, p = 0.006; p = 0.008 and p = 0.012). These results were confirmed by Kaplan-Meier survival curves. In addition, multivariate analysis using Cox regression selected the model involving stage, tumor size and smoking intensity as the quasi-independent predictor of recurrence. Conclusion: These findings suggest that cigarette smoking is an independent predictor for patients with NMIBC. Although the current evidence supports a positive link between smoking intensity and the risk of recurrence on NMIBC treated by BCG immunotherapy, additional studies, are needed before definitive conclusions can be drawn.