Breast Cancer Research and Treatment

, Volume 97, Issue 3, pp 245–254

Effects of obesity and race on prognosis in lymph node-negative, estrogen receptor-negative breast cancer

  • James J. Dignam
  • Kelly Wieand
  • Karen A. Johnson
  • Peter Raich
  • Stewart J. Anderson
  • Carol Somkin
  • D. Lawrence Wickerham
Epidemiology

DOI: 10.1007/s10549-005-9118-3

Cite this article as:
Dignam, J.J., Wieand, K., Johnson, K.A. et al. Breast Cancer Res Treat (2006) 97: 245. doi:10.1007/s10549-005-9118-3

Summary

Background

Several factors may contribute to poorer prognosis for obese breast cancer patients, including unfavorable disease features, the influence of fat on estrogen availability, co-morbidity, and socio-demographic factors. Both obesity and estrogen receptor negative (ER-) tumors are more prevalent in black women than in whites in North America. We evaluated obesity and race in relation to outcomes in women with ER-breast cancer.

Methods

Among 4077 women from National Surgical Adjuvant Breast and Bowel Project clinical trials for node-negative, ER-breast cancer, we evaluated disease-free survival (DFS) and its constituents (tumor recurrence, contralateral breast cancer (CBC), second primary cancers, deaths prior to these events) and mortality in relation to body mass index (BMI) and race, using statistical modeling to account for other prognostic factors.

Results

Compared to those of normal weight (BMI≤24.9), DFS hazard was greater for obese (BMI ≥ 30) women [hazard ratio (HR)=1.16, 95% confidence interval (CI)=1.01–1.33]. Obesity did not increase recurrence hazard, but did influence CBC (HR=2.08, 95% CI=1.22–3.55 in postmenopausal women) and second cancers (HR=1.49, 95% CI=1.06–2.10). Mortality increased with obesity; when partitioned by likely cause, those with BMI ≥ 35.0 had greater risk of non-breast cancer mortality (HR=1.86, 95% CI=1.21–2.84). Relative to whites and adjusted for BMI, black women had greater hazard for DFS (HR=1.17, 95% CI=1.00–1.38), CBC (HR=1.37, 95% CI=0.94–1.99), and non-breast cancer deaths (HR=2.10, 95% CI=1.45–3.03); risk for deaths likely due to breast cancer was closer to that in whites (HR=1.18; 95% CI=0.93–1.50).

Conclusions

For women with node-negative, ER-breast cancer from clinical trials, obesity did not increase recurrence risk, but was associated with greater risk for second cancers, CBC, and mortality, particularly non-breast cancer deaths. Less favorable prognosis for black women persists in clinical trials, and is in part attributable to non-breast cancer outcomes.

Keywords

competing risksblack womenestrogen receptor negativeobesityprognosis

Copyright information

© Springer Science+Business Media, Inc. 2005

Authors and Affiliations

  • James J. Dignam
    • 1
    • 4
    • 8
  • Kelly Wieand
    • 1
  • Karen A. Johnson
    • 2
  • Peter Raich
    • 3
  • Stewart J. Anderson
    • 4
    • 5
  • Carol Somkin
    • 6
  • D. Lawrence Wickerham
    • 7
  1. 1.Department of Health StudiesThe University of ChicagoChicagoUSA
  2. 2.Breast and Gynecologic Cancer Research Group, Division of Cancer PreventionNational Cancer InstituteBethesdaUSA
  3. 3.AMC Cancer Research Center and University of Colorado Health Sciences CenterDenverUSA
  4. 4.National Surgical Adjuvant Breast and Bowel Project (NSABP) Biostatistical CenterPittsburghUSA
  5. 5.University of PittsburghPittsburghUSA
  6. 6.Kaiser Permanente Division of ResearchOaklandUSA
  7. 7.NSABP Operations Center and Allegheny General HospitalPittsburghUSA
  8. 8.Department of Health StudiesThe University of ChicagoChicagoUSA