Refraining from Smoking for 15 Years or More Reduced the Risk of Tumor Recurrence in Non-muscle Invasive Bladder Cancer Patients

Purpose: We investigated whether smoking cessation could have preventative effects against tumor recurrence in patients with non-muscle invasive bladder cancer (NMIBC). Methods: Our study population comprised 634 patients with initially diagnosed NMIBC at Keio University Hospital, Saiseikai Central Hospital, and Saitama Medical University Hospital between 1995 and 2012. We analyzed the relationships between tumor recurrence in NMIBC and patient clinicopathological parameters, including smoking status. Results: Overall, 181 patients (28.5 %) were classified as current smokers, 154 (24.3 %) as former smokers, and 299 (47.2 %) as non-smokers. Kaplan–Meier curve analysis revealed that the tumor recurrence rate was significantly lower in the non-smoker group than in the current- and former-smoker groups (p < 0.001 and p < 0.001, respectively). In the 154 former smokers, Kaplan–Meier curve analysis revealed that smoking intensity and duration was not associated with tumor recurrence rate; however, patients with a smoking cessation period of 15 years or more had a significantly lower tumor recurrence rate than their counterparts (p < 0.001). A multivariate analysis identified a smoking cessation period of <15 years (hazard ratio [HR] 2.20; p = 0.003) and T1 tumors (HR 1.99; p = 0.013) as independent risk factors for tumor recurrence in the former-smokers subgroup. Conclusions: A positive smoking history was identified as one of the independent risk factors for bladder tumor recurrence after transurethral resection of the bladder tumor. Furthermore, refraining from smoking for 15 years or more reduced the risk of tumor recurrence in former smokers with NMIBC regardless of the intensity or duration of smoking. Therefore, smoking cessation may reduce the risk of tumor recurrence in patients with NMIBC.