PURPOSE: To evaluate whether a history of smoking or smoking during therapy after external beam radiotherapy (EBRT) for clinically localized prostate cancer is associated with increased treatment-related toxicity or disease progression.
METHODS: Of 2,358 patients receiving EBRT for prostate cancer 1988-2005, 2,156 had chart-recorded smoking histories. Patients were classified as never smokers, current smokers, former smokers, and current smoking unknown. Variables considered included quantity of tobacco use in pack-years, duration of smoking, and, for former smokers, how long before initiation of RT the patient quit smoking, when available. Median EBRT dose was 8100 Gy and median follow-up was 95 months. Toxicity was graded according to the National Cancer Institute's Common Terminology Criteria for Adverse Events.
RESULTS: Current smoking significantly increased the risks of both prostate-specific antigen relapse (hazard ratio [HR] = 1.4, P = 0.02) and distant metastases (HR = 2.37, P < 0.001), as well as prostate cancer-specific death (HR = 2.25, P < 0.001). Multivariate analysis demonstrated that smoking was also associated with increased risk of EBRT-related genitourinary toxicities (current, HR = 1.8, P = 0.02; former, HR = 1.45, P = 0.01). Smoking did not increase gastrointestinal toxicity.
CONCLUSIONS: Current smokers with prostate cancer are at increased risk of biochemical recurrence, distant metastasis, and prostate cancer-related mortality after definitive RT to the prostate. Current and former smokers, regardless of duration and quantity of exposure, are at an increased risk of long-term genitourinary toxicity after EBRT. Oncologists should encourage patients prior to therapy to participate in smoking-cessation programs to potentially lower their risk of relapsing disease and post-treatment toxicities. prostate cancer, radiotherapy, cigarette smoking, toxicity, distant metastases.
Steinberger E, Kollmeier M, McBride S, Novak C, Pei X, Zelefsky MJ. Are you the author?
Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, NY.
Reference: BJU Int. 2014 Oct 23. Epub ahead of print.