Purpose: This study was conducted to evaluate the effects of smoking on the clinical characteristics and growth trend of transitional cell carcinoma (TCC) of the bladder.
Materials and methods: In a retrospective case-control study from February 2000 to March 2003, patients with TCC of bladder, referred to our clinic, were selected and divided into high-grade and low-grade groups. Groups were matched for other known risk factors and the effect of smoking on size, number, and presenting grade of TCC in each group was evaluated.
Results: A total of 185 patients, with a mean age of 65.1 +/- 14.0 year, were included in this study, of whom 36 were females and 149 were males (male to female ratio of 4.1 to 1). Eighty-three patients were smokers (44.9%) with a mean 20.01 +/- 11.09 pack-year (range 0.75 to 60) smoking history. History of smoking was positive in 36.1% of the patients with low-grade tumors; whereas, 90% of the patients with high-grade tumors were smokers (P = 0.000, OR = 15.9, 95% CI: 6.7-36.9). There was a statistically significant correlation between the history of smoking and size and number of tumoral lesions (P = 0.000, P = 0.000, respectively). Positive history of smoking was also associated with higher grades of tumor in both men and women (OR = 12.8 and 8.8, respectively).
Conclusion: This study showed that smoking not only induces bladder cancer, but also, once it develops, it can increase the grade of tumor, resulting in worse prognosis. Thus, smoking cessation might favorably alter the course of bladder cancer.