The negative impact of tobacco smoking on survival after prostate cancer diagnosis.

Purpose: Tobacco smoking has been found to increase prostate cancer (PCa) mortality in cohorts of healthy men, but its effects on prognosis of men with PCa are still unclear. This study investigated the role of smoking on long-term survival after PCa diagnosis.

Methods: A retrospective cohort including 780 men with incident PCa previously enrolled (between 1995 and 2002) as cases in an Italian case-control study. Information on vital status up to 2013 (median follow-up 13 years) and cause of death were retrieved through health archives. Hazard ratios (HRs) of all-cause and PCa-specific death, and corresponding 95 % confidence intervals (CIs), were calculated using Cox models, adjusting for Gleason score and major confounders.

Results: Out of 263 PCa deceased patients, 81 died because of PCa. Smokers at PCa diagnosis reported increased risks of all-cause (HR = 1.5, 95% CI 1.1-2.2) and PCa death (HR = 2.0, 95% CI 1.0-3.8), as compared to never smokers. Dose-response effects emerged according to smoking intensity (HRs for >15 cigarettes/day: 1.9, 95% CI 1.3-3.0, for all causes and 2.3, 95% CI 1.1-4.9, for PCa) and duration (HRs for >45 years: 1.7, 95% CI 1.1-2.6, for all causes and 2.6, 95% CI 1.2-5.5, for PCa). Conversely, former smokers at PCa diagnosis showed no statistically significant higher risks of PCa death. The effects of smoking were consistent in strata of Gleason score.

Conclusions: Current smoking at PCa diagnosis negatively impacted PCa-specific, long-term survival, regardless of Gleason score. Our findings suggest that smoking could be a modifiable risk factor to improve prognosis of men diagnosed with PCa.