title: Late gastrointestinal toxicities following radiation therapy for prostate cancer.
abstract: BACKGROUND
  Radiation therapy is commonly used to treat localized prostate cancer; however, representative data regarding treatment-related toxicities compared with conservative management are sparse.
  
  
  OBJECTIVE
  To evaluate gastrointestinal (GI) toxicities in men treated with either primary radiation or conservative management for T1-T2 prostate cancer.
  
  
  METHODS
  We performed a population-based cohort study, using Medicare claims data linked to the Surveillance Epidemiology and End Results data. Competing risk models were used to evaluate the risks.
  
  
  METHODS
  GI toxicities requiring interventional procedures occurring at least 6 mo after cancer diagnosis.
  
  
  CONCLUSIONS
  Among 41,737 patients in this study, 28,088 patients received radiation therapy. The most common GI toxicity was GI bleeding or ulceration. GI toxicity rates were 9.3 per 1000 person-years after three-dimensional conformal radiotherapy, 8.9 per 1000 person-years after intensity-modulated radiotherapy, 5.3 per 1000 person-years after brachytherapy alone, 20.1 per 1000 person-years after proton therapy, and 2.1 per 1000 person-years for conservative management patients. Radiation therapy is the most significant factor associated with an increased risk of GI toxicities (hazard ratio [HR]: 4.74; 95% confidence interval [CI], 3.97-5.66). Even after 5 yr, the radiation group continued to experience significantly higher rates of new GI toxicities than the conservative management group (HR: 3.01; 95% CI, 2.06-4.39). Because our cohort of patients were between 66 and 85 yr of age, these results may not be applicable to younger patients.
  
  
  CONCLUSIONS
  Patients treated with radiation therapy are more likely to have procedural interventions for GI toxicities than patients with conservative management, and the elevated risk persists beyond 5 yr.
authors.affiliation: The Cancer Institute of New Jersey, New Brunswick, NJ 08903, USA.
authors.forename: Sung
authors.initials: S
authors.lastname: Kim
authors.forename: Shunhua
authors.initials: S
authors.lastname: Shen
authors.forename: Dirk F
authors.initials: DF
authors.lastname: Moore
authors.forename: Weichung
authors.initials: W
authors.lastname: Shih
authors.forename: Yong
authors.initials: Y
authors.lastname: Lin
authors.forename: Hui
authors.initials: H
authors.lastname: Li
authors.forename: Matthew
authors.initials: M
authors.lastname: Dolan
authors.forename: Yu-Hsuan
authors.initials: YH
authors.lastname: Shao
authors.forename: Grace L
authors.initials: GL
authors.lastname: Lu-Yao
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D005767:Gastrointestinal Diseases / Q000209:etiology* / Q000628:therapy; D006801:Humans; D008297:Male; D060787:Neoplasm Grading; D009367:Neoplasm Staging; D018579:Patient Selection; D016016:Proportional Hazards Models; D011471:Prostatic Neoplasms / Q000453:epidemiology / Q000473:pathology / Q000532:radiotherapy*; D011832:Radiation Injuries / Q000209:etiology* / Q000628:therapy; D011878:Radiotherapy / Q000009:adverse effects; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D018426:SEER Program; D013997:Time Factors; D014481:United States / Q000453:epidemiology