title: Modern Radiation Therapy and Cardiac Outcomes in Breast Cancer.
abstract: OBJECTIVE
  Adjuvant radiation therapy, which has proven benefit against breast cancer, has historically been associated with an increased incidence of ischemic heart disease. Modern techniques have reduced this risk, but a detailed evaluation has not recently been conducted. The present study evaluated the effect of current radiation practices on ischemia-related cardiac events and procedures in a population-based study of older women with nonmetastatic breast cancer.
  
  
  METHODS
  A total of 29,102 patients diagnosed from 2000 to 2009 were identified from the Surveillance, Epidemiology, and End Results-Medicare database. Medicare claims were used to identify the radiation therapy and cardiac outcomes. Competing risk models were used to assess the effect of radiation on these outcomes.
  
  
  RESULTS
  Patients with left-sided breast cancer had a small increase in their risk of percutaneous coronary intervention (PCI) after radiation therapy-the 10-year cumulative incidence for these patients was 5.5% (95% confidence interval [CI] 4.9%-6.2%) and 4.5% (95% CI 4.0%-5.0%) for right-sided patients. This risk was limited to women with previous cardiac disease. For patients who underwent PCI, those with left-sided breast cancer had a significantly increased risk of cardiac mortality with a subdistribution hazard ratio of 2.02 (95% CI 1.23-3.34). No other outcome, including cardiac mortality for the entire cohort, showed a significant relationship with tumor laterality.
  
  
  CONCLUSIONS
  For women with a history of cardiac disease, those with left-sided breast cancer who underwent radiation therapy had increased rates of PCI and a survival decrement if treated with PCI. The results of the present study could help cardiologists and radiation oncologists better stratify patients who need more aggressive cardioprotective techniques.
authors.affiliation: Department of Radiation Medicine and Applied Sciences, Moores Cancer Center, University of California, San Diego, La Jolla, California.
authors.forename: Isabel J
authors.initials: IJ
authors.lastname: Boero
authors.affiliation: Department of Radiation Medicine and Applied Sciences, Moores Cancer Center, University of California, San Diego, La Jolla, California.
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Paravati
authors.affiliation: Department of Radiation Medicine and Applied Sciences, Moores Cancer Center, University of California, San Diego, La Jolla, California.
authors.forename: Daniel P
authors.initials: DP
authors.lastname: Triplett
authors.affiliation: Department of Radiation Medicine and Applied Sciences, Moores Cancer Center, University of California, San Diego, La Jolla, California.
authors.forename: Lindsay
authors.initials: L
authors.lastname: Hwang
authors.affiliation: Department of Radiation Medicine and Applied Sciences, Moores Cancer Center, University of California, San Diego, La Jolla, California.
authors.forename: Rayna K
authors.initials: RK
authors.lastname: Matsuno
authors.affiliation: Department of Radiation Medicine and Applied Sciences, Moores Cancer Center, University of California, San Diego, La Jolla, California.
authors.forename: Erin F
authors.initials: EF
authors.lastname: Gillespie
authors.affiliation: Department of Radiation Medicine and Applied Sciences, Moores Cancer Center, University of California, San Diego, La Jolla, California.
authors.forename: Catheryn M
authors.initials: CM
authors.lastname: Yashar
authors.affiliation: Department of Radiation Medicine and Applied Sciences, Moores Cancer Center, University of California, San Diego, La Jolla, California.
authors.forename: Vitali
authors.initials: V
authors.lastname: Moiseenko
authors.affiliation: Department of Radiation Medicine and Applied Sciences, Moores Cancer Center, University of California, San Diego, La Jolla, California.
authors.forename: John P
authors.initials: JP
authors.lastname: Einck
authors.affiliation: Department of Radiation Medicine and Applied Sciences, Moores Cancer Center, University of California, San Diego, La Jolla, California.
authors.forename: Loren K
authors.initials: LK
authors.lastname: Mell
authors.affiliation: University Hospitals Case Medical Center, Harrington Heart and Vascular Institute, and Case Western Reserve University School of Medicine, Cleveland, Ohio.
authors.forename: Sahil A
authors.initials: SA
authors.lastname: Parikh
authors.affiliation: Department of Radiation Medicine and Applied Sciences, Moores Cancer Center, University of California, San Diego, La Jolla, California. Electronic address: j2murphy@ucsd.edu.
authors.forename: James D
authors.initials: JD
authors.lastname: Murphy
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001145:Arrhythmias, Cardiac / Q000175:diagnosis / Q000453:epidemiology; D016001:Confidence Intervals; D005260:Female; D006321:Heart / Q000528:radiation effects; D006331:Heart Diseases / Q000401:mortality / Q000628:therapy*; D006801:Humans; D006278:Medicare / Q000706:statistics & numerical data; D017202:Myocardial Ischemia / Q000150:complications / Q000209:etiology / Q000401:mortality; D062645:Percutaneous Coronary Intervention / Q000706:statistics & numerical data*; D018426:SEER Program; D000069584:Unilateral Breast Neoplasms / Q000150:complications / Q000401:mortality / Q000532:radiotherapy*; D014481:United States