title: Utilization and impact of a postmastectomy radiation boost for invasive breast cancer.
abstract: OBJECTIVE
  Additional radiation following postmastectomy radiation (PMRT) has an undefined benefit. We investigate those likely to be selected for a chest wall boost (CWB) and its effect on breast cancer survival (BCS) and overall survival (OS).
  
  
  METHODS
  A total of 4747 women diagnosed from 2005 to 2009 were treated with PMRT identified from the California Cancer Registry (CCR); 2686 (57%) received a CWB. Univariate and multivariate analyses compared those receiving and not receiving a CWB for BCS and OS.
  
  
  RESULTS
  With a median follow-up of 43.6 months, patients likely to receive a CWB were stage III (P ≤ .001), grade 3/4 (P = .03), positive nodes (P = .04), HER 2+ (P =.02). CWB was not related to BCS in the univariate (hazard ratio [HR], 1.00; 95% confidence interval [CI], 0.82-1.21), multivariate (HR, 1.04; 95% CI, 0.86 -1.26) analyses, and was not related OS for the univariate (HR, 0.92; 95% CI, 0.78-1.10), multivariate (HR, 0.95; 95% CI, 0.80-1.13) analyses. However, in multivariate analysis, patients not receiving chemotherapy who had a CWB had better BCS (HR, 1.77; 95% CI, 1.11-2.83).
  
  
  CONCLUSIONS
  The majority of patients were treated with a CWB. We found no difference in BCS or OS with the addition of a CWB.
authors.affiliation: Department of Radiation Oncology, University of California Davis Medical Center, Sacramento, California. Electronic address: jyoti.mayadev@ucdmc.ucdavis.edu.
authors.forename: Jyoti
authors.initials: J
authors.lastname: Mayadev
authors.affiliation: Biostatistics and Epidemiology, California Cancer Registry, Sacramento, California.
authors.forename: Kari
authors.initials: K
authors.lastname: Fish
authors.affiliation: Department of Radiation Oncology, University of California Davis Medical Center, Sacramento, California.
authors.forename: Richard
authors.initials: R
authors.lastname: Valicenti
authors.affiliation: Biostatistics and Epidemiology, California Cancer Registry, Sacramento, California.
authors.forename: Dee
authors.initials: D
authors.lastname: West
authors.affiliation: Department of Radiation Oncology, University of California Los Angeles Medical Center, Los Angeles, California.
authors.forename: Allen
authors.initials: A
authors.lastname: Chen
authors.affiliation: Department of Surgical Oncology, University of California Davis Medical Center, Sacramento, California.
authors.forename: Steven
authors.initials: S
authors.lastname: Martinez
authors.affiliation: Department of Radiation Oncology, University of California San Francisco Medical Center, San Francisco, California.
authors.forename: Theodore
authors.initials: T
authors.lastname: Phillips
mesh_terms: D000328:Adult; D001943:Breast Neoplasms / Q000453:epidemiology / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery*; D002140:California / Q000453:epidemiology; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008408:Mastectomy; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D018714:Radiotherapy, Adjuvant / Q000379:methods / Q000706:statistics & numerical data; D018426:SEER Program; D015996:Survival Rate