title: Physical activity, additional breast cancer events, and mortality among early-stage breast cancer survivors: findings from the WHEL Study.
abstract: OBJECTIVE
  Research suggests that physical activity is associated with improved breast cancer survival, yet no studies have examined the association between post-diagnosis changes in physical activity and breast cancer outcomes. The aim of this study was to determine whether baseline activity and 1-year change in activity are associated with breast cancer events or mortality.
  
  
  METHODS
  A total of 2,361 post-treatment breast cancer survivors (Stage I-III) enrolled in a randomized controlled trial of dietary change completed physical activity measures at baseline and one year. Physical activity variables (total, moderate-vigorous, and adherence to guidelines) were calculated for each time point. Median follow-up was 7.1 years. Outcomes were invasive breast cancer events and all-cause mortality.
  
  
  RESULTS
  Those who were most active at baseline had a 53% lower mortality risk compared to the least active women (HR = 0.47; 95% CI: 0.26, 0.84; p = .01). Adherence to activity guidelines was associated with a 35% lower mortality risk (HR = 0.65, 95% CI: 0.47, 0.91; p < .01). Neither baseline nor 1-year change in activity was associated with additional breast cancer events.
  
  
  CONCLUSIONS
  Higher baseline (post-treatment) physical activity was associated with improved survival. However, change in activity over the following year was not associated with outcomes. These data suggest that long-term physical activity levels are important for breast cancer prognosis.
authors.affiliation: Moores UCSD Cancer Center, University of California, 3855 Health Sciences Drive, San Diego, La Jolla, CA 94305-5411, USA.
authors.forename: Lisa A Cadmus
authors.initials: LA
authors.lastname: Bertram
authors.forename: Marcia L
authors.initials: ML
authors.lastname: Stefanick
authors.forename: Nazmus
authors.initials: N
authors.lastname: Saquib
authors.forename: Loki
authors.initials: L
authors.lastname: Natarajan
authors.forename: Ruth E
authors.initials: RE
authors.lastname: Patterson
authors.forename: Wayne
authors.initials: W
authors.lastname: Bardwell
authors.forename: Shirley W
authors.initials: SW
authors.lastname: Flatt
authors.forename: Vicky A
authors.initials: VA
authors.lastname: Newman
authors.forename: Cheryl L
authors.initials: CL
authors.lastname: Rock
authors.forename: Cynthia A
authors.initials: CA
authors.lastname: Thomson
authors.forename: John P
authors.initials: JP
authors.lastname: Pierce
mesh_terms: D000203:Activities of Daily Living; D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000401:mortality* / Q000534:rehabilitation; D015331:Cohort Studies; D004032:Diet; D005260:Female; D006801:Humans; D008875:Middle Aged; D009043:Motor Activity; D011379:Prognosis; D016032:Randomized Controlled Trials as Topic; D017741:Survivors