"Breast cancer is the second leading cause of cancer ieath among African-American women" [1, p.13]. (Lung cancer is first). "For the period of 1985-1989, the incidence for each 5-year age group younger than 40 years, was higher among black women than among white women" [2]. The incidence of breast cancer is increasing in both the black and white population, but young black women are getting more breast cancer and dying from it more often than young white women. Why? Researchers are well aware that two major risk factors have been more prevalent in young blacks than in whites, namely the incidence of early oral contraceptive use and having an abortion performed early in a woman's reproductive life. White and Daling addressed this issue in 1987. They noted that young black women had almost double the rate of increased breast cancer incidence compared to the rest of the population when comparing incidence rates from the mid 1970s to the late 1980s. In discussing possible reasons for the increase they stated: "Recently, two other factors have emerged as possible risk factors for breast cancer: oral contraceptive use before first pregnancy and abortion before first term pregnancy." [3, p.242]. It would seem to be very reasorzable to propose that these two risk factors are at least partly responsible for the marked increase in breast cancer incidence and mortality of young black women compared to young white women over the past 15 years.
Figure llA (constructed from data from the National Cancer Institute [4]) shows the incidence of breast cancer in both young black and white women, ages 20 to 44 years old, from the block of years of 1975 to 1979 as compared to 1988 to 1992. Young white women experienced a 10.1% increase (ie, going from 36.6 to 40.3 breast cancer "cases" per 100,000 women in the 20 to 44 year-old age group), whereas young black women experienced a 12. 6% increase, going from a rate of 40.8 to 45.6 per 100,000 women.
Oral contraceptives have two other main effects:
Figure 11B [5, p.l24] shows the relative ieath rates per 100,000 women for those under the age of 50. The mortality rate of young white females fell from 6.7 (in 1975) to 5.9 (in 1990), whereas the rate for young black women actually rose from 7.9 in 1975 to 8.9 in 1990. So from 1975 to 1990, although breast cancer mortality decreased in white women by about 9%, it increased in young black women by over 12%.
Oral contraceptives have two other main effects:
Absolutely. Table 11A shows the abortion rates for both black and white women for different age groups. Data on the abortion rate for young black women became available in 1981, and the rates of abortion for this period as well as for the 1990 to 1991 period are shown.
Table 11A: | ||||
---|---|---|---|---|
Abortion Rates in Young White and Black Women | ||||
Age | Whites | Blacks | Whites | Blacks |
1981 | 1981 | 1990-1991 | 1990-1991 | |
Under 15 | 5.1* | 27.0* | (0.8)** | (5.4)** |
15-17 | 26,0* | 51.5* | 21.0* | 57.7* |
18-19 | 56.6* | 87.9* | 46.5* | 117.4* |
* Sources: [6] and [7] (rates in abortions per 1,000 women). | ||||
** The data for women under age 15 in the 1990-1991 years was computed on a different scale than the rates for the under age 15 women in |
The data show that young black women obviously had a higher rate of abortions performed early in their reproductive lives than young white women. Although few statistics are available from the 1970s, it is highly probable that this trend was also true for the 1970s. One can also see that very young blacks (ie, those under 15) have an especially high relative rate of abortion compared to young whites -- specifically they have more than 5 times the abortion rate at this age, for both the 1981 and the 1990 to 1991 time periods.
It is true that young black women have about twice as many live births per 1,000 women as young white women, but those who have a live birth, in any given year, are almost always different women than those who had an induced abortion that year. Young black women have a higher abortion rate as well as a higher birth rate than young white women. It is also likely that many women who had an abortion performed early in their reproductive lives, especially those under the age of 15 and many of those aged 15 to 17 years old, will have chosen to abort their first child. These young women would be at an especially high risk, because the risk of having an abortion before a first full-term pregnancy (FFTP) in young women has been noted to carry a 150% increased risk according to at least one large study [8].
It is clear that young black women have had a higher rate of early OCP use than young white women. This trend has continued from the mid-1970s through at least the early 1990s and is even noted in the very young women aged 15 to 17 according to the cited data from 1982. The early use of OCPs by young black women could certainly account for their increasing breast cancer rates. It should also be noted that many young black and white women have used OCPs either before a FFTP or after an induced abortion, making them especially vulnerable because they would now have two risk factors. We must remember that early OCP use, especially when used before a woman has ever had a child, increases the risk of breast cancer. In 1990, Romieu et al's meta-analysis showed women under the age of 45 who had taken OCPs for 4 or more years prior to their FFTP had a 72% increased risk of breast cancer [RR=1.72 (1.36-2.19)] [9].
Table 11B: | ||||
---|---|---|---|---|
Percentage of Women Aged 15 to 19 Years Old
Using Oral Contraceptives [10, 11, 12] |
||||
YEAR --> | 1976 | 1982 | 1988 | 1990 |
WHITES (15-19) | 28.4&* | 12.6& | 18.9& | 16.7% |
BLACKS (15-19) | 47.0&* | 20.5 | 26.9% | 19.0% |
WHITES (15-17) | 7.6% | |||
BLACKS (15-17) | 11.8% | |||
* The 1976 data is based upon the category of: "Percentage of women aged 15-19 who ever used a contraceptive method, by first method used" [10]. |
It would appear so. Campbell et al noted that: "Our findings on adolescents support those of several authors who cited that adolescent women were more likely to use contraceptives after abortion" [13, p.819].
Yes. It was already noted that White et al commented that oral contraceptive use before a first pregnancy and abortion before a FFTP could be risk factors. [3, p.242]. Kelsey (1993) also noted that "below age 45, the higher rates (of breast cancer) in blacks than in whites in recent years have been hypothesized to reflect more frequent abortion and use of oral contraceptives among young women" [14, p.14]. Last, Mayberry et al noted that ". . .the higher breast cancer incidence rate among young black women may be explained by a higher prevalence and duration of oral contraceptive use" [15, p.1454].
Several authors have performed research specifically on black women who have breast cancer, as noted in Table llC.
Table 11C: | ||
---|---|---|
Black Women and Risk of Non-Specific OCP Use | ||
Author of Study | Percent Change | Findings |
Brinton [16] | 100% |
2.1 RR (1.2-3.5) in women under 35 who
had used OCPs for more than 5 years |
Laing [17] | 450% increase | 5.5 RR (1.1-27.1) in women <47 for ever use |
Mayberry [18] | 270% increase |
3.7 (1.3-10.3) in women age 20-39 who
took OCPs for more than 10 years |
Palmer [19] | 90% increase |
1.9 RR (1.3-2.7) in women <44 who
used OCPs for more than 1 year |
Table 11C presents a number of specific studies regarding OCP use and young black women. These results should certainly be taken seriously, especially because each of them is statistically significant. Although none of the studies specifically examined OCP use prior to a FFTP (first full-term pregnancy), these studies certainly serve as a warning that early OCP use could carry at least as much risk as those presented in Table llC.
It has already been noted by Skegg et al [20] that women who take depo-Provera (DMPA) for 2 years or more before the age of 25 have at least a 190% increased risk of developing breast cancer. According to a recent article in the Wall Street Journal [21], depo-Provera accounted for 19% of all contraceptive use in black women aged 15 to 19 years old, but only 8% of all contraceptive use in white women aged 15 to 19 years old. Hence, one might reasonably expect to find more DMPA related breast cancer among black women.
Mayberry [18] noted an odds ratio of 1.1 (0.5-2.3) for developing breast cancer with one induced abortion and 1.4 (0.5-3.8) for two or more abortions in women aged 20 to 39 years old. Laing [17] noted a 50% increased trend [RR= 1.5 (0.7-3.5)] in women under the age of 40, a 180% increase [RR=2.8 (1.0-8.1)] in women aged 41 to 49 years old and a 370% increase [RR= 4.7 (2.6-8.4)] in women over the age of 50, who had ever had an abortion. In a later study [22] Laing noted a 144% increase (RR = 2.44) in a comparison of sisters, one of whom had an abortion performed early in her reproductive life. Although this author found no study which specifically examined the effect of abortion prior to a FFTP in young black women, Mayberry and Laing's work certainly serves to warn that abortion performed early in a woman's life is likely to carry significant risk.
Yes, black women generally have more aggressive breast cancers and poorer survival rates compared to white women. Eley et al [23, p.953] estimated that when comparing white and black women who had breast cancer, black women had between a 70 to 90% increased risk of dying from breast cancer than white women, independent of the stage in which the cancer was diagnosed. He also found that black women had a 2.3-fold risk (ie, a 130% increased risk) of having estrogen negative breast tumors. (In general, estrogen negative tumors respond more poorly to treatment than do estrogen positive tumors.) Some have argued that the difference in breast cancer mortality between black and white women is a reflection of the different standards of care of women who have different incomes. Although this statement could certainly be true, it does not answer the question of why in general, black women have more aggressive breast cancer than white women, nor does it answer the question as to why breast cancer mortality rates have risen faster in young black women than in young white women.
Yes, it is possible, but not proven. As noted earlier, Olsson et al [24] found that women who took OCPs early in life developed a more aggressive type of breast cancer. The same phenomenon may certainly be occurring in black women who have a higher rate of estrogen negative tumors.
Yes, it would appear so. It was noted earlier that women who take depo-Provera (DMPA) for 2 years or more before the age of 26 have at least a 190% increased risk of developing breast cancer according to Skegg et al [20]. But a study performed on South African women in 1997 found that 72% of black women had used an injectable progestin contraceptive and that 30% of women had used one for 5 years or more [25]. The progestin used most often was either DMPA or norethisterone and these injectable hormones have been used there since the mid 1960s. The study noted that white South African women had a far lower use of these progestin hormones. In general, any race of people -- black or white -- that has a high rate of OCP or depo-Provera use, is certainly at increased risk for developing breast cancer.
1 Cancer Facts & Figures for African Americans. American Cancer Society. 1996. [Back]
Miller BA, et al. Cancer Statistics Review: 1973-1989. Bethesda, MD: National Cancer Institute, 1992. [NIH Publication Number 92-2289]3 White E, Daling J, et al. Rising incidence of breast cancer among young women in Washington State. J Natl Cancer Inst. 1987; 79: 239-243. [Back]
4 National Cancer Institute. SEER Cancer Statistics Review. 19731992: Tables and Graphs. Bethesda, Maryland. incidence rates of breast cancer in Black and White women age 20-44. [Back]
5 National Cancer Institute. SEER Cancer Statistics Review. 1973-1992: Tables and Graphs. Bethesda, Maryland. [Back]
6 Ventura S, Taffel S, et al. Trends in pregnancies and pregnancy rates, United States, 1980-1992. Monthly Vital Statistics Report. 1995; 43: 1-24. [Back]
7 Hayes CD. Risking the Future. Washington, D.C.: National Academy Press. 1987. [Back]
8 Daling J, Malone K, et al. Risk of breast cancer among young women: relationship to induced abortion. J Natl Cancer Inst. 1994; 86: 1584-1592. [Back]
9 Romieu I, Berlin J, et al. Oral contraceptives and breast cancer. Review and meta-analysis. Cancer. 1990; 66: 2253-2263. [Back]
10Zelnik M, Kantner J. Sexual activity, contraceptive use and pregnancy among metropolitan-area teenagers: 1971-1979. Family Planning Perspectives. 1980; 12: 230-237.11 Bachrach C, Mosher W. Use of Contraception in the United States, 1982. Vital and Health Statistics of the National Center for Health Statistics [U.S. dept. of Health and Human Services]. Dec. 4, 1984; Number 102: 1-8. [Back]
12 U.S. Government statistics regarding OCP use in black and white women. Source cannot be specifically cited until government publication is made public (work currently in progress). [Back]
13 Campbell NB, et al. Abortion in Adolescence. Adolescence. 1988; 23: 813-823. [Back]
14 Kelsey J, Horn-Ross P. Breast cancer: magnitude of the problem and descriptive epidemiology. Epidemiologic Reviews. 1993; 15: 7-16. [Back]
15 Mayberry RM, Stoddard-Wright C. Breast cancer risk factors among black women and white women: similarities and differences. Am J Epidemiol. 1992; 136: 1445-1456. [Back]
16 Brinton LA, Daling JR, et al. Oral contraceptives and breast cancer risk among younger women. J Natl Cancer Inst. 6/7/1995; 87: 827-35. [Back]
17 Laing AK, Demenais FM, et al. Breast cancer risk factors in African-American women: The Howard University tumor registry experience. Journal of National Medical Association. 1993; 85 (12): 931-939. [Back]
18 Maybery RM. Age-specific patterns of association between breast cancer and risk factors in black women, ages 20 to 39 and 40 to 54. Ann Epidemiol. 1994; 4: 205-213. [Back]
19 Palmer J, Rosenberg L, et al. Oral contraceptives use and breast cancer risk among African-American women. Cancer Causes and Control. 1995; 6: 321-331. [Back]
20 Skegg DCG, Noonan EA, et al. depot medroxyprogesterone acetate and breast cancer [A pooled analysis of the World Health Organization and New Zealand studies]. JAMA. 1995: 799-804. [Back]
21 Freedman AM. Why teenage girls love the shot; Why others aren't too sure. The Wall Street Journal. October 14, 1998. [Back]
22 Laing AK, Bonney GE, et al. Reproductive and lifestyle factors for breast cancer in African-American women. Genet Epidemiol. 1994: A300. [Back]
23 Eley JW, Hill HA, et al. Racial differences in survival from breast cancer. JAMA. 1994; 272: 947-954. [Back]
24 Olsson H, Borg A, et al. Early oral contraceptive use and premenopausal breast cancer -- A review of studies performed in southern Sweden. Cancer Detection and Prevention. 1991; 15: 265-271. [Back]
25 Bailie R, et al. A case-control study of breast cancer risk and exposure to injectable progestin contraceptives. S Afr Med J. 1987; 87: 302-305. [Back]