I recently became more interested in the prevalence of breast cancer since I have begun to see an alarming number of new cases in the area where I live—more than I remember for decades. The statistics are stark: In the 1940s–when good statistics began to accrue–the rate of breast cancer was about one case per eighteen women; by 2003, that rate increased to one per eight women in the United States. At that rate–and related to the possible underlying causes–some statisticians prognosticate a rate of one per five women by 2020-2033. The best evidence—according to the Breast Cancer Fund meta-analysis–suggests that the cause lies in longer exposure of the breasts to bombardment by estrogen on breast receptors. That is due to several factors—the most important of which is the earlier onset of menarche (first menstruation)–and that, in turn, is related to weight; on average, menarche occurs when a girl reaches a weight of 110-120 pounds. American girls are reaching that weight at a much earlier age, and menarche is now occurring significantly earlier than fifty and forty years ago. In fact, early onset of puberty is now the norm, rather than the exception. There remains, of course, a fairly wide range of difference among American girls. Statistically normal onset of puberty can range from ages 8-13 and takes, on average, 1.5-6 years to complete. As completion nears, more estrogen is produced; and breasts (male and female) are subjected to earlier and more prolonged influence of estrogen.
A second factor in the estrogen issue occurs at the other end of the continuum of women’s lives. Menopause is now prolonged as women take estrogen to ameliorate the symptoms of hot flashes, irregular or profuse periods, etc. In past decades, women had more pregnancies and breast fed more regularly and for longer periods of time thereby reducing the breasts’ exposure to estrogen unprotected by progesterone. Finally, American women are unfortunately more obese; fat produces estrogen, and the breasts continue to be targeted. In all probability, there are a variety of other causes of the high rate of breast cancer occurrence: environmental (including endocrine-disruptive chemicals such as PBBs and studies indicate that prenatal and early-life exposure to bisphenol A–originally developed as a synthetic hormone and now used in all polycarbonate plastics and food and beverage can lining—etc., many of which are known to mimic hormones like estrogen and can induce earlier sexual maturity), sociological, physiological, nutritional, psychological, and smoking—none of which are well enough understood. Genetics are fairly well understood, but the contribution is apparently limited.
A woman’s lifetime risk of developing breast and/or ovarian cancer is greatly increased if she inherits a harmful mutation in BRCA1 or BRCA2. That is often suspected in women who have a primary female relative—mother, sister, daughter, or grandmother, especially if she as all four. The risk in those cases is so dire that even presently cancer free girls and women should consider prophylactic bilateral mastectomy and post mastectomy prosthetic augmentation.
At present, about 12 percent of women in the general population can expect to develop breast cancer sometime during their lives. But a striking fifty-five to sixty-five percent of women who inherit the BRCA1 mutation and about forty-five percent of women who inherit a BRCA2 mutation will develop breast cancer by the age of seventy. About 1.3 percent of women in the general population will develop ovarian cancer sometime during their lives; but thirty-nine percent of women who inherit a harmful BRCA1 mutation and eleven to seventeen percent of women who inherit the BRCA2 mutation will develop ovarian cancer by age seventy.
During the 1980s—2003, estrogen was considered to be beneficial to women’s cardiac health and was prescribed in fairly high doses to millions of women. The WHI [Women’s Health Initiative] was launched in 1991 involving almost 162 million generally healthy postmenopausal women. An alarming fact emerged indicating that estrogen not only did not provide benefit to women’s hearts, but in fact was harmful; and also increased the risk of breast cancer. Almost immediately, providers stopped prescribing estrogen supplementation to most women or prescribed lower dose formulations. Studies after that time indicated that since 2003 there has been a marked decline in the rate of new breast cancer cases, although the increasing population has kept the number of cases high. No other causes appear to have changed dramatically; so, the decline appears likely to be related to the drop in use of postmenopausal hormones. Hopefully, the rate will at least stabilize at the high incidence of twelve percent; but a further significant decline is not expected.
What should women do?
- Be vigilant as a parent or as an individual. From the time girls first begin to bud breasts, they should develop the habit of regular self-examination of their breasts.
- From at least mid-adolescence on, girls should self-examine and/or have a second competent examiner palpate their breasts regularly—the same examiner and at the same time each month, usually mid-period cycle. This can be a mother, sister, pediatrician or other medical provider, or husband. The examination should be thorough and based on American Cancer Society recommendations about technique.
- Regular—usually yearly of every other year—mammograms. Consult a physician for information about radiation doses and risks vis á vis benefits of early detection.
- Strictly avoid smoking, exposure to environmental toxins, and estrogen supplementation unless a physician needs to prescribe such supplements for cause, and obesity.
- If pregnancy is desired, begin relatively early. There are many factors in family planning, but decreasing the risk of breast cancer may be afforded by multiple pregnancies. Unless there are health issues or failures in the performance of breast feeding, do it with each child and do it for a fairly prolonged period of time. The evidence is replete that breast feeding is a positive factor for the prevention of breast cancer.
- If a breast mass is suspected, do not hesitate or procrastinate. See an experienced provider ASAP; get ultrasounds, mammograms, or MRIs sooner instead of later. Avoid CT scans or chest x-rays if possible. Choose alternatives when available.
- There is a slight increase in breast cancer while women are on oral contraceptives which goes away after cessation. It may be a good idea to consider other forms of birth control.
- Get a genetic test for BRCA1 and BRCA2 early in life. Consider it an overridingly crucial test if the girl or woman has a first degree relative (one or more) who has been a victim of breast or ovarian cancer.
- Consider bilateral mastectomy and breast prosthesis augmentation if the BRCA1 and BRCA2 tests are positive.
- Lifelong healthy physical activity and strict avoidance of alcohol cuts the risk of developing breast cancer. The value of a healthy life style cannot be overemphasized.
Although these statistics are encouraging, an estimated 182,460 new cases of breast cancer will be diagnosed in American women in 2008 alone [American Cancer Society. Cancer Facts and Figures 2008. Atlanta, Georgia, American Cancer Society, 2008.]. In 1975, the incidence (the number of new cases) of breast cancer was 107 per 100,000 for white women and 94 per 100,000 for black women. Twenty-nine years later in 2004, the number of new cases per year had risen to 128 per 100,000 for white women and 119 per 100,000 for black women [U.S. Cancer Statistics Working Group. United States Cancer Statistics: 1999—2004 Incidence and Mortality Web-based Report. Atlanta: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention and National Cancer Institute, 2007.].
Even though incidence increased during that 29-year period, mortality (the rate of death) for white women decreased. In 1975, 32 per 100,000 white women died of breast cancer, but by 2003, the figure* had declined to 24.6. For black women, though, mortality increased over the same period, rising from 30 per 100,000 black women in the population in 1975 to 34.1 per 100,000 in 2003 [U.S. Cancer Statistics Working Group. United States Cancer Statistics: 1999—2004 Incidence and Mortality Web-based Report. Atlanta: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention and National Cancer Institute, 2007.]. (Figure 1 shows this trend).
Figure 1. Breast Cancer Incidence and Mortality, White Females vs.
Black Females. Age-adjusted to the 2004 U.S. standard population.
U.S. Cancer Statistics Working Group, 2007
As screening programs have become more common, more cases of breast cancer are being detected in the earlier stages of disease, when they are more easily and successfully treated. During the 1980s and 1990s, diagnoses of early stage cancer and precancerous conditions have increased considerably Since the late 1990s these rates have remained steady. At the same time, diagnoses of cases at the advanced stages have remained stable or dropped slightly. [American Cancer Society. Cancer Facts and Figures 2008. Atlanta, GA, American Cancer Society, 2008.].