Smoking and prostate cancer survival and recurrence

Abstract

Context: Studies of smoking in relation to prostate cancer mortality or recurrence in prostate cancer patients are limited, with few prostate cancer-specific outcomes.

Objective: To assess the relation of cigarette smoking and smoking cessation with overall, prostate cancer-specific, and cardiovascular disease (CVD) mortality and biochemical recurrence among men with prostate cancer.

Design, setting, and participants: Prospective observational study of 5366 men diagnosed with prostate cancer between 1986 and 2006 in the Health Professionals Follow-Up Study.

Main outcome measures: Hazard ratios (HRs) for overall, prostate cancer-specific, and CVD mortality, and biochemical recurrence, defined by an increase in prostate-specific antigen (PSA) levels.

Results: There were 1630 deaths, 524 (32%) due to prostate cancer and 416 (26%) to CVD, and 878 biochemical recurrences. Absolute crude rates for prostate cancer-specific death for never vs current smokers were 9.6 vs 15.3 per 1000 person-years; for all-cause mortality, the corresponding rates were 27.3 and 53.0 per 1000 person-years. In multivariable analysis, current vs never smokers had an increased risk of prostate cancer mortality (HR, 1.61; 95% confidence interval [CI], 1.11-2.32), as did current smokers with clinical stage T1 through T3 (HR, 1.80; 95% CI, 1.04-3.12). Current smokers also had increased risk of biochemical recurrence (HR, 1.61; 95% CI, 1.16-2.22), total mortality (HR, 2.28; 95% CI, 1.87-2.80), and CVD mortality (HR, 2.13; 95% CI, 1.39-3.26). After adjusting for clinical stage and grade (likely intermediates of the relation of smoking with prostate cancer recurrence and survival), current smokers had increased risk of prostate cancer mortality (HR, 1.38; 95% CI, 0.94-2.03), as did current smokers with clinical stage T1 through T3 (HR, 1.41; 95% CI, 0.80-2.49); they also had an increased risk of biochemical recurrence (HR, 1.47; 95% CI, 1.06-2.04). Greater number of pack-years was associated with significantly increased risk of prostate cancer mortality but not biochemical recurrence. Current smokers of 40 or more pack-years vs never smokers had increased prostate cancer mortality (HR, 1.82; 95% CI, 1.03-3.20) and biochemical recurrence (HR, 1.48; 95% CI, 0.88-2.48). Compared with current smokers, those who had quit smoking for 10 or more years (HR, 0.60; 95% CI, 0.42-0.87) or who have quit for less than 10 years but smoked less than 20 pack-years (HR, 0.64; 95% CI, 0.28-1.45) had prostate cancer mortality risks similar to never smokers (HR, 0.61; 95% CI, 0.42-0.88).

Conclusions: Smoking at the time of prostate cancer diagnosis is associated with increased overall and CVD mortality and prostate cancer-specific mortality and recurrence. Men who have quit for at least 10 years have prostate cancer-specific mortality risks similar to those who have never smoked.

FIGURE 1

Cumulative incidence of prostate cancer-specific death (P=.02, log-rank test) by smoking status prior to diagnosis Table that corresponds to Figures 1 and 2: [Table: see text]

FIGURE 2

Kaplan-Meier curves for overall mortality (P<.0001, log-rank test) by smoking status prior to diagnosis Table that corresponds to Figures 1 and 2: [Table: see text]

FIGURE 3

Risk of Prostate Cancer Mortality and Recurrence by Smoking Status & Intensity Now in separate EXCEL file (see Tab 1 for Mortality and Tab 2 for Recurrence). See footnotes in Table 2 for variables included in the multivariable model. Current smokers are the reference group. Please see the table below for the number of participants and events included in the analysis. [Table: see text]

FIGURE 3

Risk of Prostate Cancer Mortality and Recurrence by Smoking Status & Intensity Now in separate EXCEL file (see Tab 1 for Mortality and Tab 2 for Recurrence). See footnotes in Table 2 for variables included in the multivariable model. Current smokers are the reference group. Please see the table below for the number of participants and events included in the analysis. [Table: see text]