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Keywords:

  • breast cancer;
  • disparities;
  • African Americans;
  • young women

Abstract

  1. Top of page
  2. Abstract
  3. DATA AND LITERATURE
  4. ISSUES DISCUSSED DURING THE SUMMIT MEETING
  5. FUTURE DIRECTIONS FOR RESEARCH
  6. REFERENCES

BACKGROUND

African-American women younger than age 45 years have a higher risk of incidence and mortality due to breast cancer than other women. The reason for this disparity in risk is not well understood.

METHODS

This review summarizes the literature on the topic of breast cancer in young women and presents a summary of a discussion on this topic during a national forum on breast cancer among African-American women.

RESULTS

The occurrence of breast cancer among African-American women younger than the age of 45 years has not been well studied. There is a clear and long-term pattern of higher incidence and mortality and poorer survival in this population subgroup.

CONCLUSION

Research is needed to understand the reasons for these disparities and to reduce or eliminate them. Studies focused on hormonal factors, genetic factors, diet and obesity, and timely access to state-of-the-art prevention, information, screening, diagnosis, and treatment are likely to produce important new knowledge in this area. Cancer 2003;97(1 Suppl):273–9. © 2003 American Cancer Society.

DOI 10.1002/cncr.11025


DATA AND LITERATURE

  1. Top of page
  2. Abstract
  3. DATA AND LITERATURE
  4. ISSUES DISCUSSED DURING THE SUMMIT MEETING
  5. FUTURE DIRECTIONS FOR RESEARCH
  6. REFERENCES

Incidence

The incidence of breast cancer is higher among young African-American women than among white women in each age group younger than the age of 40 years, with rate ratios of 2.0 for African Americans from birth to 24 years, 1.5 at age 25–29 years, 1.4 at age 30–34 years, and 1.1 at age 35–39 years. At age 40–45 years, the breast cancer incidence rates for African-American and white women are nearly identical (119.7 vs. 119.1). After age 45–49 years, African-American women have a slightly lower age-specific incidence than white women, with rate ratios of 0.9 for age groups 50–54 years and 55–59 years and 0.8 for age groups 60–64 through 85 years and older.1 These age differences were observed for the time period of 1973–1997 (Figs. 1,2).

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Figure 1. Age specific breast cancer incidence rates, all Surveillance, Epidemiology, and End Results areas, 1973–1997. Rates are per 100,000 and age-adjusted to the 1970 U.S. standard.

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Figure 2. Age-adjusted breast cancer incidence by year of diagnosis, all Surveillance, Epidemiology, and End Results areas, 1973–1997, black and white females. Rates are per 100,000 and age-adjusted to the 1970 U.S. standard.

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Mortality Rates

Breast cancer mortality rates are higher among African-American women than among white women in all age groups from birth to 24 years and for the age group 55–59 years, with rate ratios of 2.0 from birth to 24 years, 1.4–1.6 at ages 25–29 through 40–44 years, and 1.1–1.2 at ages 45–49 through 55–59 years. At age 60–64 years, the rates are nearly identical for the two groups, at ages 65–69 through 80–84 years, the rate ratio is 0.9, and at age 85 and older, the rate ratio is 0.8 (Fig. 3).1

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Figure 3. Age specific female breast cancer mortality rates, all Surveillance, Epidemiology, and End Results areas, 1973–1997. Rates are per 100,000 and age-adjusted to the 1970 U.S. standard.

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Histology and Stage at Diagnosis

Younger African-American women have more advanced breast cancer at diagnosis compared with white women. For example, 42.1% and 7.6% of African-American women have regional and distant disease, respectively, compared with 39.3% and 4.5% of white women. Therefore, African-American women younger than 45 years old have a lower percentage of localized disease at diagnosis (45.8% vs. 52.5%; Fig. 4). Compared with 52.2% of white women, 65.5% of Young African-American women have larger tumors (2.0 cm and larger). In addition, 57.2% of African-American women versus 54.4% of white women are more likely to have lymph node-positive tumors. Younger African-American women also have a higher percentage of lymph node-positive tumors smaller than 2.0 cm (34.2% vs. 28.5%).1

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Figure 4. Female breast cancer, stage and diagnosis by race and age, all Surveillance, Epidemiology, and End Results areas, 1973–1997.

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Young African-American women have a higher prevalence of adenocarcinoma (5.3% vs. 4.4%), comedocarcinoma (3.8% vs. 2.9%), medullary carcinoma (6.7% vs. 3.9%), and all other histologic types combined (7.5% vs. 6.4%) at diagnosis than young white women. The prevalence of medullary carcinomas and comedocarcinomas in young African-American women is also higher than in either white or African-American women in the age group 45 years and older (Fig. 5).1

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Figure 5. Female breast cancer, histology by race and age, all Surveillance, Epidemiology, and End Results areas, 1973–1977.

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Hormone Receptor Status

Hormone receptor status (estrogen and progesterone) data are available for the years 1992–1997 for the Surveillance, Epidemiology, and End Results (SEER) program. Among breast cancer patients younger than 45 years old at diagnosis, white women have a higher proportion of tumors that are hormone receptor positive than African-American women (47.6% vs. 33.3%; Fig. 6).1

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Figure 6. Breast cancer among women under 45 years of age, hormone receptor status (estrogen and progesterone), among African American and white women, Surveillance, Epidemiology, and End Results, 1992–1997.

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Survival Rates

Young African-American women have the worst 5-year overall relative survival rate, i.e., 65.9%. Young white women have a 79.2% overall 5-year relative survival rate. Women 45 years of age and older have a better survival rate than women younger than 45 (81.5% for whites 45 years and older and 68.3% for African-American women 45 years and older). Young African-American women also have lower stage-specific survival rates than young white women (83.3% vs. 90.3% for localized disease; 57.9% vs. 71.6% for regional disease; and 14.9% vs. 23.8% for distant disease). These survival rates also are lower for each stage than those experienced by either African-American or white women 45 years of age and older at diagnosis (Figs. 7–9).1

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Figure 7. Relative survival, female breast cancer by race and age, all Surveillance, Epidemiology, and End Results areas. Cases diagnosed 1973–1997.

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Figure 8. Relative survival, female breast cancer by race and stage, all Surveillance, Epidemiology, and End Results areas. Cases diagnosed 1973–1997, age group 0–44 years.

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Figure 9. Relative survival, female breast cancer by race and stage, all Surveillance, Epidemiology, and End Results areas. Cases diagnosed 1973–1997, age group 45 years and older.

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Tumor Aggressiveness

Most studies have found that women younger than the age of 35, regardless of ethnicity, have a later stage of breast cancer at diagnosis, a higher prevalence of positive axillary lymph node involvement, a higher prevalence of high-grade tumors, tumors that are less well differentiated, tumors that have a higher proliferating fraction, and an earlier stage by stage recurrence. These characteristics partially explain the higher mortality rates among young women. Studies do not clearly demonstrate that these characteristics explain the higher incidence and mortality and lower survival rates among African-American women. These characteristics are often summarized as constituting more aggressive behavior. Possible explanations for the more aggressive breast cancers among young women include a greater promoting effect of higher estrogen levels, a higher grade and a higher rate of lymph node involvement among p53-positive women (more common among young women), and the greater prevalence of estrogen (ER) and progesterone receptor-negative tumors among African-American young women.2–13

Childhood Cancer Survivors

Women who are survivors of childhood cancers, particularly thyroid cancers and Hodgkin disease, have an exceptionally high risk of developing breast cancer. The highest risk of breast cancer is seen among women who had mantle-field radiation therapy for Hodgkin disease, particularly women who were diagnosed and treated as children younger than 15 years old.14–19

Obesity/Diet

Obesity has the opposite relationship to breast cancer among young breast cancer patients than that seen among women 45 years and older with breast cancer. Among younger women, the risk of breast cancer is inversely related to body mass index, to a much heavier or much lighter weight in adolescence, or to a shorter than average height at age 12–13 years.20–23

Few studies have evaluated the relationship between specific dietary patterns and breast cancer in young breast cancer patients, much less among young African-American women diagnosed with breast cancer. A study of serum carotenoids provides evidence of a protective effect for lycopene, β-cryptoxanthin, and lutein/zeaxanthin.24 Future research is needed to elucidate the role of dietary patterns and specific nutrients in the occurrence of breast cancer among young African-American women.

Studies of alcohol use and breast cancer in young women have observed an increased risk among women with both moderate and heavy alcohol use.24–26 One study found increasing risk with increasing consumption of red wine.26

Hormones and Hormonal Risk Factors

Hormonal risk factors associated with breast cancer risk include age at menarche, oral contraceptive use, and parity. Some studies have shown a higher risk of breast cancer among women who experienced earlier onset of menarche. Evaluation of factors predicting age at menarche showed that Asian/Pacific Islander, Hispanic, and African-American ethnicity predicted earlier age at menarche, even after controlling for other factors.23, 27, 28

Early oral contraceptive use has a modest effect on breast cancer risk in young women.29, 30 Another study showed that there was an odds ratio of 2.39 for Her-2/neu-positive versus Her-2/neu-negative tumors in women younger than 45 years who had taken oral contraceptives.31

Parity, particularly early age at first full-term pregnancy combined with higher overall parity, has been hypothesized to explain some of the elevated incidence of breast cancer among young African-American women.23, 32 One study showed that women younger than 30 years of age with pregnancy-associated breast cancer had lower survival, larger tumors, and more advanced-stage tumors. The advanced stage of disease at diagnosis is probably due to delays in diagnosis and treatment.33

The relationship between estrogen and progesterone status at diagnosis among young women with breast cancer is not clear. Some studies show better survival rates among hormone receptor-positive breast cancer patients, whereas others show a worse survival rate. One study suggests that adjuvant chemotherapy alone may not be adequate for young women with estrogen-positive breast cancer. A worse disease-free survival rate was observed in women if amenorrhea was not achieved as a result of chemotherapy. Analysis of ER variants in African-American women indicate that current immunohistochemical techniques used to identify receptor status in tumors cannot determine the functional status of ER.2, 4, 5, 10, 34

Genetics

Genetics, including family history and the prevalence of specific gene mutations, was not the main focus of our review of available information on the problem of breast cancer among young African-American women. Briefly, studies have shown that both a first-degree family history and specific gene mutations are associated with a higher risk of breast cancer among young women and predict poorer survival rates. In addition, studies have shown that African-American breast cancer patients have unique BRCA1 gene mutations, that there are no racial differences in polymorphic distributions of CYP17, and that young women have frequent allelic loss at 11q24.1-q25, which is associated with poor survival rates.23, 30, 35–45

Socioeconomic, Cultural, and Behavioral Factors

Few studies have focused on the cultural, behavioral, and socioeconomic factors associated with advanced disease at diagnosis, poor prognosis, and poor survival rates among breast cancer patients. These factors include a low income, Medicaid enrollment, lack of private health insurance, poor transportation, beliefs that women who have breast surgery are no longer attractive to men, beliefs that air causes a cancer to spread, beliefs that chiropractic is effective treatment for breast cancer.46, 47

ISSUES DISCUSSED DURING THE SUMMIT MEETING

  1. Top of page
  2. Abstract
  3. DATA AND LITERATURE
  4. ISSUES DISCUSSED DURING THE SUMMIT MEETING
  5. FUTURE DIRECTIONS FOR RESEARCH
  6. REFERENCES

The session focused on several risk factors of breast cancer in young African-American women, including age, race, and ethnicity; diet, nutrition, and obesity; hormones and hormonal risk factors; behavioral, cultural, and socioeconomic effects; and genetics.

Risk Factors

Age, race, and ethnicity

Young women around the country repeatedly report that physicians state that young women do not get breast cancer. The mindset seems to be that it “just doesn't happen.” Are age, race, and ethnicity critical risk factors? It was agreed that a research agenda should be set to address this question. There is considerable mythology surrounding breast cancer among young women: if a patient does not show evidence of all the risk factors, the medical profession does not believe the patient can have the disease. Because of physician bias, it is important that young women be educated about breast cancer risk, as well as the medical profession.

Considerable discussion focused on identifying the unique risk factors for breast cancer in young African-American women. The first issue was to define the term “young” before developing generalities about the African-American population. Some members of the group believed that young should begin at conception, whereas others defined young as those younger than the age of 40. Although a specific definition was not developed, it was agreed that this is an issue that researchers must clarify.

Other issues that were raised included 1) the lack of knowledge of clinical trials by the medical profession, 2) health care providers who do not encourage patients with a poor prognosis to participate in clinical trials, and 3) the ignorance or lack of knowledge on the part of the health professionals.

Diet, nutrition, and obesity

It was agreed that diet, obesity, and nutrition offer potential for prevention in the future. Various research groups are studying the role each plays in breast cancer etiology and many of these studies include reasonable numbers of African-American women.

Hormones and hormonal risk factors

Hormonal variables are being studied; however, what is less often encompassed by current research is investigation into when the exposure to risk factors begins and whether there are ages during which exposure is particularly critical. It is clearly the case that postmenopausal breast cancer is different than breast cancer occurring among premenopausal women. One of the notable differences is the hormonal milieu in which tumors arise in premenopausal versus postmenopausal women. What is not clear is whether the premenopausal group has at least two subgroups (very young, perhaps younger than the age of 40 years and age 40 years to menopause).

Much of the concern about external environmental risk factors, such as the concern about pesticides, is due to the hormonelike behavior of some pesticides. The group identified two problems with current breast cancer screening methods. First, current screening methods cannot identify breast cancers at the earliest, molecular stages. Second, there is no efficacious screening method for women younger than the age of 40 years. There is a need for new methods of screening and diagnosis, particularly for methods that will be efficacious in young women.

Genetics

After considerable discussion, the group agreed that extensive research is needed in this area, including studies of the ethical aspects of genetic testing and confidentiality of results. Collection of data on genetic mutations involves privacy of the family, as well as privacy of the individual.

Behavioral, cultural, and socioeconomic effects

Based on the comments of the participants, it was agreed that research should focus on identifying behavioral, cultural, and socioeconomic risk factors for breast cancer through screening of breast cancer survivors and newly diagnosed patients.

Recommendations

The participants were asked to provide ideas for future research. The following recommendations resulted from that discussion:

  • 1
    Conduct more focus groups, case–control studies, and population studies.
  • 2
    Screen the children of young breast cancer survivors as a follow-up measure.
  • 3
    Address some infrastructure issues (e.g., collaborations between the Centers for Disease Control and Prevention and the National Cancer Institute, as well as collaborations between the SEER program and the North American Association of Central Cancer Registries) for the purpose of expanding SEER to include African-American regional populations.
  • 4
    Study young African-American women with breast cancer.
  • 5
    Educate young women and health care providers.
  • 6
    Conduct more community-based research.
  • 7
    Educate the African-American community about the risk factors in young women.
  • 8
    Develop effective communication through an appropriate message given by “messengers” to the community.
  • 9
    Include African-American women who were diagnosed with breast cancer in research.
  • 10
    Engage African-American organizations (e.g., the National Association for the Advancement of Colored People, Sister to Sister, National Dialogue on Cancer, National Black Leadership Conference, National Coalition of Black Women, National Medical Association, Black Nurses' Association, and sororities) to address breast cancer issues and provide leadership for African-American women with breast cancer.
  • 11
    Conduct support groups specifically for the African-American community.

FUTURE DIRECTIONS FOR RESEARCH

  1. Top of page
  2. Abstract
  3. DATA AND LITERATURE
  4. ISSUES DISCUSSED DURING THE SUMMIT MEETING
  5. FUTURE DIRECTIONS FOR RESEARCH
  6. REFERENCES

The specific area of breast cancer among African-American women who are younger than the age of 45 years has not been well studied. One study showed that the usual risk factors do not explain the high breast cancer risk of young African-American women.48 Research directed toward explaining the higher incidence and mortality and poorer survival rates in this population is needed. Fruitful areas of investigation, based on the descriptive data and published research, include studies of diet, obesity, hormonal factors, and genetics as etiologic factors, as well as studies of timely access to information, screening, diagnosis, treatment, and state-of-the-art care for breast cancer patients.

REFERENCES

  1. Top of page
  2. Abstract
  3. DATA AND LITERATURE
  4. ISSUES DISCUSSED DURING THE SUMMIT MEETING
  5. FUTURE DIRECTIONS FOR RESEARCH
  6. REFERENCES