A new study presented at the annual San Antonio Breast Cancer Symposium has reported that African-American women with hormone receptor positive (estrogen receptor positive (ER+) and progesterone receptor positive (PR+)) breast cancer have worse cancer outcomes than the general U.S. population. Previously, it had been reported that black women were more likely to die after diagnosis with breast cancer and this was attributed to a higher rate of triple negative (ER-/PR-/Her2-) disease, differences in care, and other concurrent diseases. The study included 4,950 women with lymph node positive or high-risk node-negative breast cancer, all of whom underwent surgery, were administered chemotherapy, and received standard hormonal therapy if hormone receptor positive. Four hundred and sixteen of the study participants (8.4%) were black. Study endpoints included disease free survival and overall survival.
As expected, black women had higher rates of triple negative disease (34% compared to 19%) and higher median body mass index (32.0 vs. 27.7). However, not expected was the finding that black race was associated with worse disease free survival and worse overall survival in the hormone receptor positive group, but not in the triple negative or HER2-overexpressing group. The association between black race and poor outcome held among hormone receptor positive women after body mass index and other prognostic variables were controlled for. The authors conclude that factors other than disparities in care or more advanced or aggressive disease may have contributed to breast cancer recurrence in this group.
Other studies have reported lower survival rates for African Americans
It is well known that African-American women are less likely to survive breast cancer than Caucasian women (77% versus 90% five-year survival, according to the latest available 2008 figures). It has been thought that this discrepancy is the result primarily of the fact that African-American women are more likely to present at later stages with more aggressive types of breast cancer (e.g., triple negative and inflammatory breast cancer). Discrepancies in care are also known to be a factor. For example, a recent study reported that older African-American women with early stage breast cancer are significantly less likely than Caucasian women to receive radiotherapy after lumpectomy even though this is the standard of care for early-stage breast cancer. Other factors, such as the fact that African-American women are more likely to progress to breast cancer from benign breast disease than non-African-American women, also play a role. However, the current study is the first to report lower survival among African-American women who have the most common type of breast cancer and receive appropriate treatment.
Strategies to improve outcome of hormone receptor positive breast cancer
Hormone receptor positive (ER+/PR+) breast cancer is responsive to hormonal treatments. Every effort should be made to complete tamoxifen and/or aromatase inhibitor treatment after primary breast cancer treatment such as chemotherapy and radiation. There are a number of foods that are estrogenic and should be avoided and others that oppose estrogen and may be beneficial. These foods are listed in our hormone receptor positive breast cancer web page.
African-American women might also consider taking steps to minimize exposure to the following possible sources of estrogenic compounds:
- Hair care and other products marketed to African-American women that contain placenta or "hormone." Personal care products containing lavender, tea tree oil or parabens
- Herbal supplements and formulations designed to treat menopausal symptoms containing estrogenic herbs such as licorice
- Food and beverage containers made with (1) polyvinyl chloride (PVC) (may be found in cling wrap, some plastic squeeze bottles, and cooking oil bottles); (2) polystyrene (styrofoam food containers and disposable cups and bowls); or (3) polycarbonates (plastic water bottles). (These products should be used only temporarily and at low temperatures. Plastic containers may be marked with a number in a triangle-like icon. Plastics marked 1, 2, 4 or 5 use less toxic additives in their manufacture. Products that use polyvinyl chloride should be marked with 3, polystyrene with a 6, and polycarbonate with a 7 - these are the ones to avoid)
- Air pollution and runoff from nearby farms, oil refineries, chemical plants, water treatment facilities or military bases.
Adequate levels of vitamin D have been found to be associated with reduced risk of breast cancer and improved prognosis. However, vitamin D photosynthesis is one-third as efficient in African-American compared to Caucasian women and vitamin D insufficiency is more than five times as common. Some observers have suggested that this is one reason for the disparity in survival between the two groups. African-American breast cancer survivors should have their levels of vitamin D checked (with a simple blood test) and steps taken to increase the level if it is found to be low.
Since fat cells are a source of estrogen, excess weight can also contribute to less favorable prognosis after a breast cancer diagnosis. In addition, type 2 diabetes and metabolic syndrome are associated with poorer outcomes, apparently because excess circulating insulin can also promote breast cancer growth.