Black Women and Breast Cancer

Chris Kahlenborn
(chapter eleven)
Breast Cancer: Its link to Abortion
and the Birth Control Pill
Reproduced with Permission

"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.

Q-11A. What has happened to the incidence of breast cancer in young black and white women over the past 25 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.

Figure 11A:

Oral contraceptives have two other main effects:

Q-11B: What about the mortality rate in young white and black women?

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%.

Figure 11B:

Oral contraceptives have two other main effects:

Q-11 C: In accordance with these findings, one might expect young black women to have a higher incidence of abortions performed early in their reproductive lives and/or a history of early OCP (oral contraceptive pill) use. Does the historical data support this?

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 llA:

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.

Q-11D: Young black women also have more early live births than young white women. Does this not protect them from breast cancer, because having a child at a younger age decreases a woman's risk of developing breast cancer?

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].

Q-11E: What do the records show concerning early OCP use among young white and black women?

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 llB:

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].

Q-11F: Do women who haue abortions really have a higher rate of OCP use?

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].

Q-11G: Have any researchers commented upon the probable connection between early OCP use, abortion, and breast cancer when taken/performed by/on young women?

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].

Q-11H: What have the specific studies of oral contraceptive pill use and breast cancer shown in young black women?

Several authors have performed research specifically on black women who have breast cancer, as noted in Table llC.

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.

Q-11I: Could the use of depo-Provera be another part of the explanation as to why young black women are getting breast cancer more frequently than young white women?

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.

Q-11J: What about the risk of abortion as concerns breast cancer in young 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.

Q-11K: Do black women have "worse" breast cancer than white women?

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.

Q-11L: Could the fact that Eley et al found that black women had more estrogen negative tumors be a result of their increased early OCP use and history of more frequent abortions?

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.

Q-11M: Are black women in any other countries at high risk of developing breast cancer?

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.


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