BACKGROUND-AIM:
Conventional combustible cigarette smoking is the primary modifiable risk factor for the development and adverse prognosis of bladder cancer (BCa). Continued smoking after a BCa diagnosis has been consistently linked to poorer clinical outcomes. This systematic review and meta-analysis synthesizes existing quantitative evidence to precisely estimate the prognostic risk (Hazard Ratios, HRs) of continued smoking versus cessation on BCa recurrence and mortality, providing crucial data for clinical counseling.

METHODS:
A systematic literature review and quantitative synthesis (meta-analysis) of published studies were conducted, focusing on bladder cancer patients with documented smoking status changes post-diagnosis. Studies reporting Hazard Ratios (HRs) for Recurrence, Cancer-Specific Mortality (CSM), and Overall Mortality were included. Data from recent high-quality meta-analyses were pooled to calculate Summary Hazard Ratios (SHRs) for risk comparisons against never-smokers or patients who achieved cessation.

RESULTS:
The meta-analysis confirms that smoking status significantly worsens the prognosis of patients diagnosed with bladder cancer (BCa). Current smokers face a significantly worse prognosis across all tracked endpoints compared to never smokers. Current smokers have a 21% to 28% increased risk of Overall Mortality (SHR 1.21–1.28) and a 24% increased risk of Cancer-Specific Mortality (SHR 1.24). Furthermore, continued smoking raises the risk of Recurrence by 24% to 33% (SHR 1.24–1.33). Even former smokers retain a 22% increased risk of recurrence compared to never smokers, demonstrating the long-term impact of past exposure. Crucially, studies on post-diagnosis intervention show that quitting smoking at or near diagnosis leads to a substantial benefit compared to continued smoking. Cessation is associated with a 29% reduction in the hazard of Overall Survival (SHR 0.71) and a 36% to 41% reduction in the hazard of Recurrence/Progression (SHR 0.59–0.64).

CONCLUSIONS:
Continued combustible smoking after a bladder cancer diagnosis significantly increases the risk of overall mortality, cancer-specific mortality, and disease recurrence by over 20% compared to never smokers. Crucially, cessation at the time of diagnosis is associated with a clinically meaningful 29-41% reduction in the hazard of adverse outcomes compared to continued smoking. This strongly supports the necessity of aggressive smoking cessation efforts in all patients diagnosed with bladder cancer to improve prognosis.