title: Long-term mortality from cardiac causes after adjuvant hypofractionated vs. conventional radiotherapy for localized left-sided breast cancer.
abstract: OBJECTIVE
  Ongoing concern remains regarding cardiac injury with hypofractionated whole breast/chest-wall radiotherapy (HF-WBI) compared to conventional radiotherapy (CF-WBI) in left-sided breast cancer patients. The purpose was to determine if cardiac mortality increases with HF-WBI relative to CF-WBI.
  
  
  METHODS
  Between 1990 and 1998, 5334 women with early-stage breast cancer received post-operative radiotherapy to the breast/chest wall alone. A population-based database recorded baseline patient, tumor and treatment factors. Baseline cardiovascular risk factors were identified from hospital administrative records. A propensity-score model balanced risk factors between radiotherapy groups. Cause of death was coded as breast cancer, cardiac or other cause. Cumulative mortality from each cause after radiotherapy was estimated using a competing risk approach.
  
  
  RESULTS
  For left-sided cases, median follow-up was 14.2 years. 485 women received CF-WBI, 2221 women received HF-WBI. There was no difference in 15-year mortality from cardiac causes: 4.8% with HF-WBI and 4.2% with CF-WBI (p=0.74), even after propensity-score adjustment (p=0.45). There was no difference in breast cancer mortality or other cause mortality. For right-sided cases, there was no difference in mortality for the three causes of death.
  
  
  CONCLUSIONS
  At 15-years follow-up, cardiac mortality is not statistically different among left-sided breast cancer patients treated with HF-WBI or CF-WBI.
authors.affiliation: Department of Oncology, Saint John Regional Hospital, Canada.
authors.forename: Elisa K
authors.initials: EK
authors.lastname: Chan
authors.affiliation: BC Cancer Agency, Cancer Control Research Department, Vancouver, Canada.
authors.forename: Ryan
authors.initials: R
authors.lastname: Woods
authors.affiliation: Division of Cardiology, University of British Columbia, Vancouver, Canada.
authors.forename: Sean
authors.initials: S
authors.lastname: Virani
authors.affiliation: BC Cancer Agency, Breast Cancer Outcomes Unit, Vancouver, Canada.
authors.forename: Caroline
authors.initials: C
authors.lastname: Speers
authors.affiliation: BC Cancer Agency, Radiation Therapy Program, Victoria, Canada.
authors.forename: Elaine S
authors.initials: ES
authors.lastname: Wai
authors.affiliation: BC Cancer Agency, Radiation Therapy Program, Vancouver, Canada.
authors.forename: Alan
authors.initials: A
authors.lastname: Nichol
authors.affiliation: BC Cancer Agency, Cancer Control Research Department, Vancouver, Canada.
authors.forename: Mary L
authors.initials: ML
authors.lastname: McBride
authors.affiliation: BC Cancer Agency, Radiation Therapy Program, Vancouver, Canada. Electronic address: styldesl@bccancer.bc.ca.
authors.forename: Scott
authors.initials: S
authors.lastname: Tyldesley
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D005260:Female; D006321:Heart / Q000528:radiation effects*; D006331:Heart Diseases / Q000209:etiology* / Q000401:mortality; D006801:Humans; D008875:Middle Aged; D011832:Radiation Injuries / Q000209:etiology* / Q000401:mortality; D018714:Radiotherapy, Adjuvant / Q000009:adverse effects / Q000401:mortality; D012307:Risk Factors; D035441:Thoracic Wall; D055815:Young Adult
keywords: Breast cancer; Cardiac mortality; Hypofractionation