There has been much publicity involving the successful treatment for breast cancer. At the same time little is written about the risks of various medical treatments and procedures which can lead to breast cancer. The purpose of this article is to examine the pathophysiology of breast cancer associated with several unreported means of prevention. The primary sources for this article are the results of research of Dr. Angela Lanfranchi, M.D. a specialist in breast surgery and Joel Brind, Ph.D. a professor of Human Biology and Endocrinology. They have founded the Breast Cancer Prevention Institute: (www.bcpinstitute.org) Please visit their web site for further details and literature.

It is fairly well known that women who have had full term pregnancies or who have breast fed their babies have less risk of breast cancer. It is also accepted medical knowledge that woman who have never been pregnant and woman who have a family history of breast cancer or a genetic predisposition such as the BRCA gene have an increased risk of breast cancer. In the last thirty years, the incidence of breast cancer has increased by 40% in the United States primarily in younger woman. The question as to why is a focus of recent research.

It is reported in the National Cancer Institute’s Surveillance, Epidemiology, and National Vital Statistics System mortality data (available at http://www.cdc.gov/nchs/deaths.htm) that breast cancer rates by age, race, and cancer stage at diagnosis in the United States during the years 2005 to 2009 among women of all races, occurred at a rate of 205,246 breast cancers each year. Those statistics represent 121 women per 100,000. It was also reported that since 1973, invasive breast cancer has increased by 40% and non-invasive (in-situ) breast cancer has increased by 400%, (Breast Cancer Prevention Institute: The Why’s of Breast Cancer) Dr. Lanfranchi has reviewed the scientific literature in order to provide an explanation of the causes of the increase rate of breast cancer. The following information is taken from: Normal Beast Physiology, The reasons Hormonal Contraceptives and Induced abortion Increase Breast-Cancer Risk, Angela Lanfranchi, M.D., F.A.C.S., The Linacre Quarterly August 2009: 236-249 and from www.bcpinstitute.org.

According to the studies cited above, there are three major causes of breast cancer. The first cause is damaged genes resulting from mutations caused by radiation or a chemically induced injury to the gene. Secondly there can be an inherited predisposition to breast cancer such as the presence of BRCA genes. This cause involves the normal maturation of breast lobules. The third risk factor involves accumulative lifetime exposure to estrogen. I will review each one of these risk factors.

Ten percent of breast cancer arises from DNA mutations in breast cells. DNA mutations can be caused by heredity, radiation, chemicals, or spontaneous errors during DNA duplication. When there is an increased number of immature breast lobules present for random mutations, this condition exacerbates the occurrence of cancer. To understand the significance of this phenomenon, it is important to understand the normal maturation of breast lobules.

Type 1 breast lobules are immature breast lobules which exist in abundance prior to pregnancy. Once pregnancy occurs, Type 1 lobules begin to increase the number of ductules which become mammary glands from an average of 11 ductules per lobule to 47 ductules per lobule. This marks a change of type 1 lobules into type 2 lobules. Type 1 lobules have a greater number of estrogen and progesterone receptors in their cells and are the sites where about 80% of all breast cancers arise. While Type 2 lobules are more mature, they still are the sites where about 10% of breast cancers start. Type 2 lobules eventually mature still more fully into Type 3 lobules which have very few estrogen/progesterone receptors. These cells do not quickly copy their DNA, which decreases the possibility of mutations and carcinogenesis. By thirty-two weeks Type 3 lobules start to produce colostrum, becoming Type 4 lobules which are resistant to cancer. This explains why women are generally resistant to cancer after their first full term pregnancy.

The breast maturation process that protects a woman from breast cancer happens because the baby in her womb produces the hormones hCG (human chorionic gonadotropin) and hPL (human placental lactogen). HCG stimulates estrogen and progesterone levels in the early pregnancy to increase the number of Type 1 and Type 2 lobules. In the latter half of the pregnancy hPL levels which are three times higher than the mother’s prolactin levels enables full differentiation to Type 4 lobules. When a woman’s breasts mature to Type 4 lobules she has a lifelong reduction in breast cancer risk.

A woman is most protected from breast cancer when her baby comes to full term. A pregnancy ending between thirty-two and thirty-six weeks has about 90% of the protective effect of a full term pregnancy. On the other hand premature delivery before thirty-two weeks is known to result in more than double breast cancer risk because it leaves the breasts with an increase of number of type 1 and type 2 lobules which have a higher risk of spontaneous mutations. In other words there are more places for cancer to start. Premature delivery and induced abortion have the same breast cancer risk. There is a 3% increase in breast cancer risk for each week of gestation before an abortion. When a woman has an abortion after a full term pregnancy she will have the lifelong breast cancer protection from the first full term pregnancy. When she has had an abortion prior to her first full term pregnancy, the risk for breast cancer is far greater. This is because the hormones of pregnancy stimulate breast proliferation of type 1 and 2 lobules which increase the probability of random mutations to cancer cells and if there has already been a cancer mutation, the estrogen levels in pregnancy stimulate the proliferation of the cancer cells. What about a spontaneous abortion or miscarriage? Does that have the same risk factors? Research shows that a first trimester miscarriage does not increase the risk of breast cancer because pregnancy hormones are lower than in a normal pregnancy. Because of this, the breasts do not increase the number of type 1 and type 2 lobules, and there is not an increased risk of breast cancer in miscarriages.

The third factor for increased risk of breast cancer is the lifelong exposure to estrogen. Estrogen is a natural hormone produced primarily in the ovaries which is necessary for normal breast development and fertility. However, estrogen has also long been known to be associated with breast cancers. Before there were effective chemotherapy drugs physicians would remove a breast cancer patient’s ovaries reducing the patient’s estrogen levels in order to slow the growth of her breast cancer. Too much estrogen can cause cancer in two ways. Estrogen stimulates cell division, mitosis, which can cause random mutation of normal cells to cancer cells and then it can stimulates growth of the cancer cells. Estrogen or its metabolite can also act as a carcinogen by directly damaging DNA, thereby causing cancer cells to form. Drugs such as Tamoxifen which block estrogen from attaching to breast cell receptors are used to treat breast cancer.

In August 2010 the World Health Organization listed combined estrogen/progesterone birth control pills as a Group 1 carcinogen. This is the group of carcinogens which also includes substances such as arsenic, asbestos, and plutonium. In 2006 a meta-analysis published in the Mayo Clinic Proceedings showed a 44% increase risk of breast cancer in woman who took combination birth control pills before their first pregnancy. (Kahlenborn C, et al. “Oral Contraceptive Use as a Risk Factor for Premenopausal Breast Cancer: a Meta-analysis”, 2006 Mayo Clinic Proceedings 2006: 81 (10):1290-1302.) Yet doctors continue to write these prescriptions for women without informing them of their increased risk of breast cancer.

In summary, it is standard medical practice to inform patients of the risk or benefit of a medication or treatment. The current research data indicates that there is an increased risk of breast cancer in woman who have had an induced abortion before their first full term pregnancy. In August 2010 the World Health Organization listed combined estrogen/progesterone birth control pills as a Group 1 carcinogen. The WHI study terminated early in 2002 partially because of increase in breast cancer with the use of post-menopausal Hormone Replacement Therapy (HRT) and partially because of increased cardiovascular risks. The current scientific literature indicates that an increase in lifelong estrogen exposure from birth control pills or HRT increases the risk of breast cancer. It is important that this information becomes public knowledge and a standard part of informed consent documentation in the medical profession. There was a time when the tobacco industry prevented the labeling of cigarettes as potential causes of lung cancer. This is now common knowledge and all cigarette packages have a warning. The hope is that the risks of breast cancer as discussed above will be a requirement of informed consent and package labeling. Women have a right to know the risks of any medication or medical procedure.

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