Purpose: To evaluate the impact of tobacco smoking on specific histological subtypes of transitional cell carcinoma of the bladder (TCC).
Methods: Between 2003 and 2009, we conducted a hospital-based case-control study in Italy, enrolling 531 incident TCC cases and 524 cancer-free matched patients. Odds ratios (OR) and corresponding 95% confidence intervals (CI) were estimated through multiple logistic regression models.
Results: Compared to never smokers, TCC risk was threefold higher in former smokers (95% CI 2.07-4.18) and more than sixfold higher in current smokers (95% CI 4.54-9.85). TCC risk steadily increased with increasing intensity (OR for ≥25 cigarettes/day 8.75; 95% CI 3.40-22.55) and duration of smoking (OR for ≥50 years 5.46; 95% CI 2.60-11.49). No heterogeneity emerged between papillary and non-papillary TCCs for smoking intensity and duration, but the risk for those who had smoked for ≥50 years was twice for non-papillary TCC (OR 10.88) compared with papillary one (OR 4.76). Among current smokers, the risk for a 10-year increase in duration grew across strata of intensity (p-trend = 0.046). Conversely, the risk for a 5-cigarette/day increase in smoking intensity was quite steady across strata of duration (p-trend = 0.18).
Conclusions: Study results suggested that duration of smoking outweighs intensity in determining TCC risk, with limited differences across histological subtypes. Elimination of tobacco smoking may prevent about 65 % of TCCs.