title: The Impact of Radiation Oncologists on the Early Adoption of Hypofractionated Radiation Therapy for Early-Stage Breast Cancer.
abstract: Despite multiple randomized trials showing the efficacy of hypofractionated radiation therapy in early-stage breast cancer, the United States has been slow to adopt this treatment. The goal of this study was to evaluate the impact of individual radiation oncologists on the early adoption of hypofractionated radiation therapy for early-stage breast cancer.
  
  
  
  We identified 22,233 Medicare beneficiaries with localized breast cancer that was diagnosed from 2004 to 2011 who underwent breast-conserving surgery with adjuvant radiation. Multilevel, multivariable logistic models clustered by radiation oncologist and geographic practice area were used to determine the impact of the provider and geographic region on the likelihood of receiving hypofractionated compared with standard fractionated radiation therapy while controlling for a patient's clinical and demographic covariates. Odds ratios (OR) describe the impact of demographic or clinical covariates, and the median OR (MOR) describes the relative impact of the individual radiation oncologist and geographic region on the likelihood of undergoing hypofractionated radiation therapy.
  
  
  
  Among the entire cohort, 2333 women (10.4%) were treated with hypofractionated radiation therapy, with unadjusted rates ranging from 0.0% in the bottom quintile of radiation oncologists to 30.4% in the top quintile. Multivariable analysis found that the individual radiation oncologist (MOR 3.08) had a greater impact on the use of hypofractionation than did geographic region (MOR 2.10) or clinical and demographic variables. The impact of the provider increased from the year 2004 to 2005 (MOR 2.82) to the year 2010 to 2011 (MOR 3.16) despite the publication of long-term randomized trial results in early 2010. Male physician and radiation oncologists treating the highest volume of breast cancer patients were less likely to perform hypofractionation (P<.05).
  
  
  
  The individual radiation oncologist strongly influenced the likelihood of a patient's receiving hypofractionated radiation therapy, and this trend increased despite the publication of long-term data showing equivalence to standard fractionation. Future research should focus on physician-related factors that influence this decision.
authors.affiliation: Department of Radiation Medicine and Applied Sciences, 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, 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, University of California, San Diego, La Jolla, California.
authors.forename: Jiayi
authors.initials: J
authors.lastname: Hou
authors.affiliation: Department of Radiation Medicine and Applied Sciences, 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, University of California, San Diego, La Jolla, California.
authors.forename: Ellen
authors.initials: E
authors.lastname: Kim
authors.affiliation: Department of Radiation Medicine and Applied Sciences, 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, University of California, San Diego, La Jolla, California.
authors.forename: Catheryn
authors.initials: C
authors.lastname: Yashar
authors.affiliation: Department of Radiation Medicine and Applied Sciences, University of California, San Diego, La Jolla, California.
authors.forename: Loren K
authors.initials: LK
authors.lastname: Mell
authors.affiliation: Department of Radiation Medicine and Applied Sciences, 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; D001943:Breast Neoplasms / Q000473:pathology* / Q000532:radiotherapy* / Q000601:surgery; D016009:Chi-Square Distribution; D015331:Cohort Studies; D003657:Decision Making; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D015412:Mastectomy, Segmental; D006278:Medicare / Q000706:statistics & numerical data; D009367:Neoplasm Staging; D016017:Odds Ratio; D000072103:Oncologists / Q000706:statistics & numerical data*; D010818:Practice Patterns, Physicians' / Q000706:statistics & numerical data; D011365:Professional Practice Location; D000069473:Radiation Dose Hypofractionation; D018787:Radiation Oncology / Q000706:statistics & numerical data*; D018714:Radiotherapy, Adjuvant / Q000379:methods; D018426:SEER Program; D012737:Sex Factors; D014481:United States