Birth Control Pills Increased Risk Of Breast Cancer. A recent article by the New York Times described a study that reveals a disturbing finding: women who use birth control pills, or other forms of contraception that contain hormones, are at an increased risk for developing breast cancer. Though the increase in risk is small, it is significant.
The study followed close to 2 million Danish women for more than ten years. Though many women believed that modern birth control pills are much safer than those their mothers and grandmothers took decades ago, the study shows otherwise. Previously, many believed that the higher doses of estrogen in birth control was the problem. Today’s marketed birth control pills contain much lower doses of the hormone.
A correlation between breast cancer and birth control pills was discovered many years ago. However, the Danish study is the first to look at the risk associated with current forms of birth control in such a large group.
Interestingly, few differences in the amount of risk were uncovered when the different types of birth control were studied side by side. Birth control implants, which may be placed in the arm, and intrauterine devices (IUDs), which are placed directly in the uterus, did not significantly reduce the risk of breast cancer.
In fact, the study revealed that progestin, which is a hormone used in many types of birth control, may increase the risk of breast cancer.
The study estimates that for every 100,000 women on hormonal contraceptives, an additional 13 new cases of breast cancer will be diagnosed every year. In general, there are 55 cases in women who do not use these types of birth control; it is estimated that there will be 68 annual cases in women who do use hormonal birth control.
Dr. Marisa Weiss, an oncologist who was not involved with the study, commented, “This is an important study because we had no idea how the modern day pills compared to the old-fashioned pills in terms of breast cancer risk, and we didn’t know anything about IUDs. Gynecologists just assumed that a lower dose of hormone meant a lower risk of cancer. But the same elevated risk is there.”
Dr. Weiss further stated, “It’s small but it’s measurable, and if you add up all the millions of women taking the pill, it is a significant public health concern.”
The study did not examine all of the factors that may impact a woman’s breast cancer risk, such as breastfeeding, alcohol consumption, and exercise.
The American College of Obstetricians and Gynecologists issued a statement advising that they will carefully examine the new study results. Officials commented that, for many women, hormonal contraceptives are “among the most safe, effective and accessible options available.”
It is important to note that birth control pills have many benefits, including reducing the risk of other types of cancer. Birth control pills are associated with a lower risk of endometrial cancer and ovarian cancer, and some also believe it reduces the risk of colorectal cancers for older women.
Dr. Chris Zahn, the vice president for practice activities of the American College of Obstetricians and Gynecologists, emphasized that women should discuss their birth control options with their medical providers before making any changes. He explained, “It’s important that women feel confident and comfortable with their contraceptive choice.”
Dr. Weiss noted that since the risk for breast cancer increases as women get older, some women may want to consider a birth control method that does not release hormones. Diaphragms and condoms are options, as well as hormone-free IUDs. Dr. Weiss said, “It’s not like you don’t have a choice. Why not pursue another option?”
The study was published in the New England Journal of Medicine. David J. Hunter, who teaches epidemiology and medicine at the University of Oxford, explained that the study shows that no modern contraceptives are without their risks. “There was a hope that the contemporary preparations would be associated with lower risk. This is the first study with substantial data to show that’s not the case,” he explained.
In the United States, close to 10 million women rely on oral contraceptives for birth control. Approximately 1.5 million women use oral contraceptives for other reasons, such as treating acne and other conditions. An increasing number of women have turned to IUDs and other hormonal implants in recent years.
Previous types of oral contraceptives were known to increase a woman’s risk of breast cancer. However, many medical professionals, as well as their patients, had assumed that newer pills with lower hormone doses reduced the risk. However, this study reveals that the current risk is similar to those reported in the 1980s and before.
Lisa S. Mørch, the lead author of the paper and a senior researcher at the University of Copenhagen, commented, “We did actually expect we would find a smaller increase in risk because today we have lower doses of estrogen in hormone contraceptives, so it was surprising that we found this association.”
Additionally, the study showed that the risk increased with time—the longer oral contraceptives were used, the greater the risk of developing breast cancer. Dr. Mørch said, “It is a very clear picture for us, very convincing.”
The 1.8 million Danish women in the study were of childbearing age. Researchers analyzed data from Danish cancer and national prescription registries. During the study, which lasted more than ten years, 11,517 cases of breast cancer were diagnosed.
Overall, researchers estimate that hormonal birth control users face a 20 percent increase in the risk of breast cancer when compared to those who do not take hormonal birth control. The risk does increase with age and varies by formulation. The increased risk, according to researchers, results in just a few additional cases of breast cancer.
Young women are at a low risk of developing breast cancer; however, those who used hormonal birth control for more than 10 years saw an increase in risk—by approximately 38 percent. Even for those who only used hormonal birth control for a five-year period, the increase in risk was present even after they stopped using the birth control. In women who used hormonal birth control for less than a year, no increased risk of breast cancer was detected.
Women who used IUDs that contained only progestin faced a 21 percent increase in developing breast cancer. Thus, researchers gathered that progestin might increase the risk of breast cancer.
A grant for the study was provided by Novo Nordisk Foundation, which supports medical research at both public institutions and within the Novo Group. Novo Nordisk is a worldwide healthcare company that primarily focuses on diabetes management; it also manufactures Vagifem, which is an estrogen insert for menopausal women. Dr. Mørch and another of the study’s authors have been employed by the company since the study was accepted for publication.