title: Obesity is associated with a poorer prognosis in women with hormone receptor positive breast cancer.
abstract: OBJECTIVE
  Whether moderate to severe obesity (body mass index (BMI)≥30 to <40kg/m(2)) contributes to breast cancer recurrence and mortality remains uncertain.
  
  
  METHODS
  1199 women, recruited within 12 months of their diagnosis of hormone receptor positive (HR+), human epidermal growth factor receptor 2 negative (HER2-) invasive breast cancer completed an enrolment questionnaire and an annual follow-up questionnaire every 12 months for another 5 years. The impact of obesity on time to either local or distant recurrence or new breast cancer, or death due to breast cancer was determined by Cox regression. Women in the most extreme categories of BMI (<18.5 and ≥40) were excluded from the analysis.
  
  
  RESULTS
  Of the 1155 included women, mean age, 58.4±11.6 years, 53.8% had Stage 1 disease and 88.9% received oral adjuvant endocrine therapy (OAET) within 2 years of diagnosis. The likelihood of an event was significantly associated with moderate to severe obesity (HR=1.71, 95%CI, 1.12-2.62, p=0.014), disease beyond Stage 1 (HR=2.87, 95% CI 1.73-4.75, p<0.001), OAET (HR=0.26, 95%CI 0.14-0.46, p<0.001), mastectomy (HR=3.28, 95%CI 1.98-5.44, p<0.001) and radiotherapy (HR=2.12, 95%CI 1.24-3.63, p=0.006). For Stage 1 disease, only moderate to severe obesity (HR 3.23, 95%CI 1.48-7.03, p=0.003) and OAET use (HR 0.41, 95%CI 0.17-0.98, p=0.046) were significantly associated with an event.
  
  
  CONCLUSIONS
  Moderate to severe obesity is associated with a poorer invasive breast cancer prognosis; this is also true for women with Stage 1 disease, and is independent of age and treatment.
authors.affiliation: Women's Health Research Program, School of Public Health and Preventive Medicine, Monash University, 99 Commercial Road, Melbourne, Victoria 3004, Australia.
authors.forename: Penelope J
authors.initials: PJ
authors.lastname: Robinson
authors.affiliation: Women's Health Research Program, School of Public Health and Preventive Medicine, Monash University, 99 Commercial Road, Melbourne, Victoria 3004, Australia.
authors.forename: Robin J
authors.initials: RJ
authors.lastname: Bell
authors.affiliation: Women's Health Research Program, School of Public Health and Preventive Medicine, Monash University, 99 Commercial Road, Melbourne, Victoria 3004, Australia. Electronic address: susan.davis@monash.edu.
authors.forename: Susan R
authors.initials: SR
authors.lastname: Davis
mesh_terms: D000368:Aged; D015992:Body Mass Index; D001943:Breast Neoplasms / Q000628:therapy*; D018270:Carcinoma, Ductal, Breast / Q000628:therapy; D018275:Carcinoma, Lobular / Q000628:therapy; D002423:Cause of Death; D017024:Chemotherapy, Adjuvant; D015331:Cohort Studies; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008408:Mastectomy / Q000379:methods; D015412:Mastectomy, Segmental / Q000379:methods; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D009364:Neoplasm Recurrence, Local / Q000209:etiology; D009367:Neoplasm Staging; D009765:Obesity / Q000150:complications*; D011379:Prognosis; D018714:Radiotherapy, Adjuvant; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000032:analysis; D011960:Receptors, Estrogen / Q000032:analysis; D011980:Receptors, Progesterone / Q000032:analysis; D012307:Risk Factors; D015996:Survival Rate
chemical_list: D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; C508053:ERBB2 protein, human
keywords: Breast cancer; Obesity; Recurrence; Survival