The Impact of Tobacco Use on Outcomes and Toxicity in a Predominantly Minority Population of Males with Prostate Cancer Receiving External Beam Radiation.

INTRODUCTION

To investigate whether current or prior smoking history had any impact on prostate cancer outcomes and toxicity in our predominantly minority population of males receiving dose-escalated external beam radiation therapy (EBRT).

METHODS

Of the 500 patients treated with EBRT between 2003-2011, 444 had smoking histories recorded. Patients were classified as current smoker, former smoker, or never smoker. Biochemical failure-free survival (BFFS) and distant metastatic-free survival (DMFS) endpoints were analyzed. Multivariate Cox regression and multivariate logistic regression were used to assess whether smoking had an impact on outcomes and toxicity respectively.

RESULTS

There were 176 males (39.6%) classified as never smokers, 169 (38.1%) as prior smokers, and 99 (22.3%) as current smokers. The median follow-up was 76 months (range nine-146) and 61.9% of patients were African American. The eight-year BFFS for never smokers, prior smokers and current smokers was 73.6%, 80.2%, and 73.4% respectively, p=0.38. Similarly, the eight-year DMFS was 92.8%, 96.8%, and 95.3% respectively, p=0.54. On multivariate analysis, prior smoking (HR 0.72, p=0.19) and current smoking (HR 1.02, p=0.93) were not associated with increased biochemical failure. Similarly, smoking use was not associated with increased distant metastatic disease (hormone receptor (HR) 0.71, p=0.51 for prior smokers, HR 1.41, p=0.52 for current smokers). The presence of intermediate-risk disease (HR 2.87, p=0.002) was associated with an increased likelihood of biochemical failure. The high-risk disease was associated with both a higher risk of biochemical failure (HR 8.02, p <0.001) as well as distant metastatic disease (HR 17.61, p=0.01). On multivariate regression, prior or current smoking use was not associated with an increased likelihood of late grade two genitourinary or gastrointestinal toxicity.

CONCLUSION

Current or prior smoking use was not associated with inferior outcomes or increased toxicity in this study comprising a predominantly minority population undergoing dose escalated radiation therapy for prostate cancer.