Editor's note. National Right to Life News ran its first article on the link between induced abortion and an increase in the occurrence of breast cancer in the December 7, 1993, edition. In the ensuing eleven and a half years, the "right to life newspaper of record" has addressed the connection in dozens of different ways, often by refuting studies that purport to "prove" there is no such link.
We have certainly written about the biology that explains why there is a heightened risk of breast cancer when a woman chooses to abort. But at a workshop at NRLC's 2004 convention, Dr. Angela Lanfranchi offered the most detailed physiological explanation to date to explain what has come to be known as the "ABC link." She titled her talk, "The Irrefutable Biological Basis of the Abortion-Breast Cancer Link."
The following is an adaptation of Dr. Lanfranchi's talk. It is well worth reading and saving.
Dr. Lanfranchi is vice president of the Breast Cancer Prevention Institute. You can read much more about abortion and breast cancer risks on its website-www.bcpinstitute.org.
Simply stated, the increased risk for contracting breast cancer because a woman has chosen to abort rests on two simple, interrelated biological principles.
The first is that the more estrogen a woman is exposed to in her lifetime, the higher her risk for breast cancer. The second is the sooner she matures her undifferentiated, cancer-vulnerable Type 1 lobules into the cancer-resistant Type 3 lobules, the lower her risk for breast cancer. The only "mechanism" for this transformation is a process that takes place in the third trimester of pregnancy called differentiation.
PREGNANCY, ESTROGEN, AND BREAST CANCER
The first principle concerning the effect of estrogen exposure is the hardest to grasp, even counter-intuitive. After all, estrogen is a normal female hormone in a woman's body and is what makes women womanly. Without it women could not have children.
There are two ways estrogen can induce cancers to form: as a genotoxin and a mitogen. A genotoxin directly damages the DNA causing mutations, which initiates a process that leads to the formation of cancer.
A mitogen causes cells to pro-liferate, that is, to multiply through division. Each a time a cell divides to form two cells, it must replicate its DNA.
But during replication, there are mutations in the form of "copying" errors. Much like really bad typos can change the meaning of a sentence or even make the whole sentence wrong, if this "error" is severe enough, a cancer cell can form.
What does this have to do with breast cancer?
When a woman becomes pregnant, estradiol, a type of estrogen, causes her breasts to enlarge. This estradiol rush causes a huge increase ("proliferation") in the number of cancer-vulnerable cells in her breasts and an increase in the number of Type 1 and Type 2 lobules.
The second biological principle which explains why induced abortion increases the risk of breast cancer risk concerns the protective role a full-term pregnancy plays by maturing a woman's breast lobules into Types 3 and 4, which are much more resistant to carcinogens. (Type 4 lobules form after childbirth.)
Women are born with a small number of Type 1 breast lobules, which are units of milk glands and duct cells. At adolescence, because of estrogen, a young woman develops some Type 2 lobules. Types 1 and 2 lobules are faster growers than Type 3 lobules and, compared to Type 4 lobules, have a shorter doubling time.
Type 1 lobules, otherwise known as terminal ductal lobular units (TDLU), are where we know ductal cancers start.
However, after she completes a full-term pregnancy, 70% of a woman's breast lobules have become mature, cancer-resistant Type 3 lobules. In the process the growth potential - - and cancer-forming potential - - of these cells is turned off. Simply put, there are now fewer places for breast cancers to start.
When these two principles are considered together it becomes apparent why induced abortion increases breast cancer risk.
Even before implantation, as soon as a woman conceives, her estrogen levels start to rise. By the end of the first trimester in a healthy pregnancy the level has risen by 2000%.
But if a pregnancy is stopped prior to week 32, the woman is left with many more Type 1 and 2 lobules than before she became pregnant. (If pregnancy had gone to term, these lobules would have been protected from cancer because they had matured into Type 3 and 4 lobules.) So, rather than having fewer places for cancer to form, she has more.1
It is the interplay of these two principles, estrogen exposure and breast lobule maturation, which accounts for the fact that abortion can lead to breast cancer.2
The biology of the ABC link is vital for all women to understand in its own right but also important to keep in mind when the latest epidemiological study comes out purportedly showing that there is no link between induced abortion and breast cancer.
But no study can change our biology or what we have witnessed in our own communities. Over the past 30 years, cumulative lifetime risk of breast cancer has gone from 1 in 12 to 1 in 7 women.
The women with breast cancer in our neighborhoods are getting younger and younger. Every woman who understands her own biology knows why.
Dr. Lanfranchi is a clinical assistant professor of surgery at the Robert Wood Johnson Medical School in Piscataway, New Jersey. In addition, she a fellow of the American College of Surgeons, a diplomate of the American Board of Surgery, and a member of the Expert Advisory Panel for the New Jersey Board of Medical Examiners.