Smoke load prognostic impact on bacillus Calmette-Guérin (BCG) treated non-muscle invasive bladder cancer.

Purpose: Smoking habit is the major risk factor for bladder cancer (BC), related to about 50% of these tumors; however, the tobacco dose-effect impact on BC immune treatment is underexplored. This study evaluates the impact of smoke load on non-muscle invasive bladder cancer (NMIBC) prognosis after intravesical BCG.

Methods: Smoke load, recurrence, progression and disease-specific survival were evaluated in a retrospective study including NMIBC patients treated with intravesical BCG between 2006 and 2015. Multivariate Cox regression, ROC and Kaplan-Meier curves were utilized.

Results: 132 pT1 NMIBC patients were included: 95 (72%) males, mean age 69.6 ± 10.5 years and mean smoking pack-years 22.0 ± 20.8. Recurrence, progression and disease-specific death occurred in 69 (52.3%, mean 20.55 ± 20.44 months), 22 (16.7%, mean 31.39 ± 20.19 months) and 11 (8.3%, mean 37.23 ± 18.34 months), respectively. Smoke load significantly impacted recurrence, HR = 1.019 (95% CI 1.008-1.030, p = 0.0004), and progression, HR = 1.034 (95% CI 1.016-1.052, p = 0.0002), but not survival. For every 1-year increment in pack-years, the risk of relapse and progression increases by 1.9% and 3.4%, respectively. Over 20 pack-year showed the best predictive prognostic power.

Conclusion: The smoke load has a potential prognostic role in terms of recurrence and progression in the BCG treated NMIBC. Future studies should explore the smoking impact on the immune system, mainly beyond 20 pack-year.