Risk Factors and Breast Cancer Survival in Black/White Women

Institution: Beckman Research Institute of the City of Hope
Investigator(s): Yani  Lu , M.D. -
Award Cycle: 2009 (Cycle 15) Grant #: 15FB-0004 Award: $89,996
Award Type: Postdoctoral Fellowship
Research Priorities
Disparities>Disparities: eliminating the unequal burden of breast cancer



Initial Award Abstract (2009)

Eliminating racial disparities in cancer mortality by the year 2015 is an American Cancer Society challenge goal. To date, the disparity in breast cancer mortality between black women and white women is still increasing with black women having the highest mortality rates. The reasons for this racial disparity are not completely understood. Risk factors for breast cancer incidence may promote the development of specific types of breast cancer, and thus influence the course of disease and have an effect on survival. Although data on relationship between risk factors and breast cancer survival are increasing, few studies provide detailed information on multiple risk factors and few data on these relationships exist for black women.

In this project, we will use the unique opportunity provided by the Women’s Contraceptive and Reproductive Experiences (CARE) Study to investigate the association between established breast cancer risk factors and their effect on all-cause mortality and breast cancer-specific mortality. We will also examine whether these risk factors explain at least, in part, the racial disparity in breast cancer survival between black women and white women. Our aims to determine whether breast cancer survival is affected by a woman’s:

  1. family history of breast cancer
  2. body size measures including height, weight, body mass index (kg/m2, BMI), and weight change before diagnosis
  3. recreational physical activity before diagnosis
  4. reproductive characteristics including age at menarche, parity, age at first full-term pregnancy, and time since most recent birth and breastfeeding
  5. use of exogenous hormones (oral contraceptives and menopausal hormone therapy)

For this study we will use participants in the Women’s CARE Study, which enrolled 2953 white and 1622 black invasive breast cancer patients aged 35 to 64 years, have been followed for survival since their diagnoses between 1994 and 1998. Since completing a detailed interview on breast cancer risk factors shortly after diagnosis, 1044 (511 black and 533 white) have died with 793 deaths (394 black and 399 white) attributed to breast cancer.

Identifying lifestyle and other factors that modify the risk of mortality following breast cancer will enhance our ability to improve the survival experience of women diagnosed with breast cancer. It will help us predict whether specific subgroups have an increased risk of mortality. It will also provide leads to understanding the underlying biology mechanisms influencing prognosis, and thus will provide potential solutions for clinical decision for breast cancer patients.




Final Report (2011)

To date, the disparity in breast cancer mortality between black and white women is still increasing with black women having higher mortality rates than white women. The reasons for this racial disparity are not completely understood. Identifying lifestyle and other factors that modify the risk of mortality following breast cancer will enhance our ability to improve the survival experience of women diagnosed with breast cancer. It will help us predict whether specific subgroups have an increased risk of mortality, and help us understand underlying mechanisms influencing prognosis, and thus will provide potential solutions for clinical decision for breast cancer patients.

In the past two years, we have completed our aims on whether family history of breast cancer, body mass index, oral contraceptive use affect breast cancer survival and whether these factors explain the poorer survival of black women. We found that women with family history of breast cancer had a similar risk of mortality compared with women without family history; obesity (body mass index=30 kg/m2) at 5-year before breast cancer diagnosis increased the risk of death among white women but not among black women even though the prevalence of obesity was higher among black women (26.9%) than white women (12.1%). Thus, it is unlikely that different distribution of obesity among black women and white women diagnosed with breast cancer account for the poorer survival of black women. We also found that oral contraceptive use before breast cancer diagnosis has no assocaiton with survival, in both black women and white women.

During this process, we also developed new aims by investigating whether alcohol consumption and co-morbidities before breast cancer diagnosis affect survival. We found that women who had higher level of alcohol consumption before breast cancer diagnosis had a lower risk of death from any cause and from breast cancer, and these risk patterns were observed for wine, but not for beer or liquor. The prevalence of co-morbidities was higher among black women than among white women (61% vs. 45%). Compared to women without any co-morbidities, women with more comorbidities had increasing risk of death, especially for those diagnosed with locialized tumors. This risk pattern was consistent among black women and white women.

Due to the two new created aims, we were not able to finish other proposed aims (reproductive factors and recreational physical activity) in two years. We are going to continue working on this project and finish all the prposed aims in the near future.




Symposium Abstract (2010)

Yani Lu (PI), Huiyan Ma, Jane Sullivan-Halley, Sophia S Wang, Katherine D. Henderson, James V Lacey Jr., Leslie Bernstein (mentor)

Objective: To examine if prediagnostic oral contraceptive (OC) use influences survival among women with invasive breast cancer.

Methods: 4564 women ages 35 to 64 years with newly diagnosed invasive breast cancer participated in the Women’s Contraceptive and Reproductive Experiences (CARE), a study of risk factors for breast cancer, between 1994 and 1998. Since then (median follow-up=8.6 years), 1055 of these women died, 828 from breast cancer. Multivariable adjusted relative risks and 95% confidence intervals were estimated for risk of all-cause mortality and breast cancer-specific mortality using Cox proportional hazards models. Models included race, study site, tumor stage, estrogen receptor status and tumor grade to account for their effects on survival.

Results: Women who used OC for over 10 years had a 21% decrease in risk for death from any cause and a 12% decrease in risk for death from breast cancer when compared to women who never used oral contraceptives. These effects were stronger among women who reported a family history of breast cancer and women who used oral contraceptives within ten years of their breast cancer diagnosis.

Conclusions: Our results suggest that oral contraceptive use may have a favorable influence on survival for breast cancer patients; although the underlying characteristics of oral contraceptive users or unmeasured factors influencing oral contraceptive use might also contribute to the associations we observed in this study and thus require further investigation.



Obesity and survival among black women and white women 35 to 64 years of age at diagnosis with invasive breast cancer.
Periodical:Journal of Clinical Oncology
Index Medicus: J Clin Oncol
Authors: Lu Y, Ma H, Malone KE, Norman SA, Sullivan-Halley J, Strom BL, et l, and Bernstein L
Yr: 2011 Vol: 29 Nbr: 25 Abs: Pg:3358-65

Oral contraceptive use and survival in women with invasive breast cancer.
Periodical:Cancer Epidemiology Biomarkers and Prevention
Index Medicus: Cancer Epidemiol Biomarkers Prev
Authors: Lu Y, Ma H, Malone KE, Norman SA, et al, and Bernstein L
Yr: 2011 Vol: 20 Nbr: 7 Abs: Pg:1391-7