Background

of newly diagnosed cases of bladder cancer are low grade, noninvasive and papillary tumors [1]. The standard treatment for non-muscle invasive bladder cancer (NMIBC) is transurethral resection of the bladder tumor (TUR-BT) with or without adjuvant intravesical instillation (IVI) of chemotherapy or Bacillus Calmette-Guerin (BCG) therapy [2]. The most important problems associated with NMIBC are that they have high rates of recurrence and risk of progression. Ap-proximately 50 % to 70 % of NMIBC have a recurrence within 5 years, and 5 % to 20 % progress to invasive tu-mors [3]. To the best of our knowledge, there have been no reports with longer follow-up data focusing on the ef-fects of IVI on tumor recurrence and progression in pa-tients with low grade Ta tumors based on the 2004 WHO classification [4,5]. Also, there are few publishe