This article was published in a "point-counterpoint" format on the opinion page of the Philadelphia Inquirer on October 6, 2002. The contrary view was offered by Polly Newcomb, a research scientist with joint appointments at the Fred Hutchinson Cancer Center in Seattle and at the University of Wisconsin Comprehensive Cancer Center.
Breast cancer is epidemic in developed countries, yet in developing countries it remains an uncommon illness. Scientists seeking to unravel the mystery now have a much clearer picture of why this is happening. As Eugenia Calle, the director of analytic epidemiology for the American Cancer Society in Atlanta put it last week: "The dramatic changes that have occurred in childbearing over the past 50 to 75 years really can explain a fairly large amount of breast cancer incidence in developed countries"(1).
Two critical changes in childbearing have occurred in the west this century: millions of women have chosen to delay childbearing until later in life, and millions have chosen to interrupt childbearing through abortion. Some have applauded these trends as beneficial to personal health and social prosperity. Yet two recent scientific developments, examining the effects of breastfeeding and the effects of abortion on the subsequent development of breast cancer, underscore the negative impact of these dramatic social changes on the health of American women.
The breastfeeding study (BFBC), published this month in The Lancet, was a statistical analysis of data from 47 studies worldwide dating back to 1970, the year when the protective effect of breastfeeding on breast cancer was first proposed (2). The abortion and breast cancer study (ABC) published in 1996 was a statistical analysis of data from all 23 studies available throughout the world dating back to 1957, when a connection between induced abortion and breast cancer was first observed (3).
The BFBC analysis showed that breastfeeding for 6 months or more after delivery effectively reduces the risk of breast cancer, and that “the major reasons for the high incidence rates of breast cancer are the small family size and short duration of breastfeeding that were characteristic of women in (developed) countries” (2). Health organizations are now reviewing existing guidelines on breastfeeding to modify them in light of this new data.
The ABC study showed that abortion was a risk factor for breast cancer, and that the detrimental effect was related directly to the interruption of pregnancy. Predictably, this report generated controversy beyond scientific circles, but the quality of the analysis is undisputed (and was endorsed by the Royal College of Obstetrics and Gynecology in
The strength of this evidence should be enough to convince an objective observer that abortion can lead to breast cancer. Yet abortion providers such as Planned Parenthood have refused to inform women considering abortion of the link. Until last month, even a National Cancer Institute “fact sheet” claimed no likely association between abortion and breast cancer. On June 19, NCI director Andrew Von Eschenbach pulled the “fact sheet” and ordered several NCI divisions to review the issue, a tacit acknowledgment that the epidemiologic data linking breast cancer and induced abortion fits in well with accepted notions of breast biology from a range of scientific perspectives.
Simply stated, the primary function of the breast is to make milk, and until milk is actually produced for the first time the breast is never fully developed. Completion of breast development through lactation seems to be critically important to prevent breast cancer. That’s why having children early in life exerts a profoundly protective effect against breast cancer later in life, and why women who have no children have higher rates of breast cancer than those who have one or more.
The first pregnancy is, for many reasons, a momentous biological event for a woman. Estrogen hormones, which during pregnancy are produced by the developing fetus, reach the highest levels ever, about 20-fold higher than any other time in a woman’s life. These hormones normally accelerate the growth of breast cells, and prepare them for milk production. Milk is not made until after delivery, and if lactation never occurs, full development -– technically termed “terminal differentiation” of breast glands -- never occurs. Most scientists believe that terminal differentiation of breast cells is requisite for protection against cancer. Breastfeeding simply allows breast cells to do what they were made to do. Termination of a pregnancy stops production of fetal estrogen. It is the physiologic equivalent of slamming the brakes on breast development, and opening the door to a host of molecular derangements that can end in cancer.
The prevailing ideology of developed countries pressures women and men to delay childbearing in favor of careers, consumption and affluence, and leads some in the medical professions to ignore abundant scientific data indicating that choosing to avoid breastfeeding or to interrupt a pregnancy are not healthful practices. We should be careful to allow science rather than ideology to guide our work. If ideology prevails over objectivity, the patients we should serve will become the victims of our bias rather than the beneficiaries of our hard-earned knowledge.