title: Cigarette smoking during external beam radiation therapy for prostate cancer is associated with an increased risk of prostate cancer-specific mortality and treatment-related toxicity.
abstract: OBJECTIVE
  To evaluate whether a history of smoking or smoking during therapy after external beam radiotherapy (EBRT) for clinically localised prostate cancer is associated with increased treatment-related toxicity or disease progression.
  
  
  METHODS
  Of 2358 patients receiving EBRT for prostate cancer between 1988 and 2005, 2156 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. The median EBRT dose was 8100 Gy and the 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 showed that smoking was also associated with increased risk of EBRT-related genitourinary toxicities (current smoker, HR 1.8, P = 0.02; former smoker, 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 to participate in smoking-cessation programmes before therapy to potentially lower their risk of relapsing disease and post-treatment toxicities.
authors.affiliation: Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
authors.forename: Emily
authors.initials: E
authors.lastname: Steinberger
authors.affiliation: Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
authors.forename: Marisa
authors.initials: M
authors.lastname: Kollmeier
authors.affiliation: Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
authors.forename: Sean
authors.initials: S
authors.lastname: McBride
authors.affiliation: Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
authors.forename: Caroline
authors.initials: C
authors.lastname: Novak
authors.affiliation: Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
authors.forename: Xin
authors.initials: X
authors.lastname: Pei
authors.affiliation: Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Zelefsky
mesh_terms: D000368:Aged; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D011471:Prostatic Neoplasms / Q000453:epidemiology / Q000401:mortality* / Q000532:radiotherapy*; D011878:Radiotherapy / Q000009:adverse effects / Q000706:statistics & numerical data*; D012189:Retrospective Studies; D012907:Smoking / Q000009:adverse effects* / Q000453:epidemiology*
keywords: cigarette smoking; distant metastases; prostate cancer; radiotherapy; toxicity