Birth Control Pills Still Associated with Breast Cancer, Study Finds

The study found few distinctions in risk between the formulations; women cannot protect themselves by turning to implants or intrauterine gadgets that to push out a hormone directly into the uterus.

The research also shows that the hormone progestin – trusted in today’s birth control methods – may be raising breast cancer risk.

“This is an important study because we had no idea how the modern day pills compared to the old-fashioned pills when it comes to breast cancer risk, and we didn’t know any thing about I.U.D.’s,” said Dr. Marisa Weiss, an oncologist who founded the website breastcancer.org and was not involved in the study. “Gynecologists merely assumed a lower dose of hormone designed less risk of cancer. But the same elevated risk will there be.”

“It’s small but it’s measurable, and in the event that you add up all the millions of ladies taking the pill, it is a significant public health concern,” Dr. Weiss added.

The study was limited, the authors said, because they could not take into account factors like exercise, breast feeding and alcohol consumption, which might also influence breast cancer risk.

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Officials with the American University of Obstetricians and Gynecologists said that they would carefully evaluate the new findings, but emphasized that hormonal contraceptives are actually for many women “being among the most safe, effective and accessible possibilities.”

Authorities noted that oral contraceptives have some benefits as good, and are associated with reductions found in ovarian, endometrial and possibly colorectal cancers later found in life.

Dr. Chris Zahn, A.C.O.G.’s vice president for practice activities, acknowledged a connection between breast malignancy risk and hormone employ, but urged concerned ladies to consult a reliable medical provider prior to making changes. “It’s essential that women feel confident and comfortable with their contraceptive choice,” he said.

Because risk increases with era, Dr. Weiss recommended that older women may want to consider switching to a hormone-free birth control method, like a diaphragm, an I.U.D. that will not launch hormones, or condoms. “It’s nothing like you don’t possess a choice,” she said. “Why not pursue another option?”

In a commentary accompanying the new study, which was published in the brand new England Journal of Medicine, David J. Hunter, a professor of epidemiology and medicine at the University of Oxford, said the new study didn’t find that any modern contraceptives were risk-free.

“There was a hope that the modern day preparations would be associated with lower risk,” he said within an interview. “Here is the first study with substantial data showing that’s false.”

Almost 10 million American women use oral contraceptives, including about 1.5 million who count on them for reasons apart from birth control. The number of women in america with intrauterine devices, many of which discharge hormones, has grown in recent years, as has the number of ladies using other types of hormonal contraceptive implants.

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Although older oral contraceptives were known to increase the risk of breast cancer, various doctors and patients had assumed the newer generation of pills on the market today were safer. The new study found increased risks that were related in magnitude to the heightened risks reported in earlier analyses based on birth control products used in the 1980s and before, Dr. Hunter said.

“We did actually expect we would find a smaller increase in risk because today we have lower doses of estrogen in the hormone contraceptives, so it was surprising that people found this association,” stated Lina S. Mørch, a senior researcher at the University of Copenhagen and the paper’s business lead author.

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The study also found that the risk increased the longer women used contraceptives involving hormones, suggesting the relationship is causal, Dr. Mørch said. “This is a very distinct picture for all of us, very convincing.”

The study, which used most of Denmark as its sample, followed nearly 1.8 million ladies of childbearing era for over a decade on average, drawing data from national prescription and cancer registries. During that time frame, 11,517 conditions of breast malignancy were identified.

The researchers figured hormone users total experienced a 20 percent increase in the relative risk of breast cancer compared to nonusers, although the risk increased with age and varied by formulation. Even now, the additional risk would lead to a comparatively few further cases of breast malignancy, the researchers said.

The increase in breast cancer cases associated with hormones was also small because young women are at low risk to begin with. But the chances rose among ladies who applied hormonal contraception for a lot more than ten years, the study found. Among those that applied hormones for five years, an increased breast malignancy risk persisted even once they discontinued employ, Dr. Mørch said.

What really surprised the researchers was that the increased risk was not confined to ladies using oral contraceptive products, but also was seen in ladies using implanted intrauterine gadgets, or I.U.D.’s, which contain the hormone progestin. (Not all I.U.D.’s release hormones.)

Women who used an intrauterine product that releases only progestin also faced a good 21 percent increase in risk, weighed against nonusers, the study found. The findings indicate that the hormone progestin is increasing breast cancer risk; some of the contraceptive products and many of the I.U.D.’s included only progestin, Dr. Mørch said.

A 20 percent increase in relative risk may be tiny in absolute terms, however the calculation improvements with age. For a 20-year-old girl, for example, the probability of developing breast malignancy in the next 10 years is .06 percent, or 1 in 1,732, relating to breastcancer.org.

Even if the relative risk increases 20 percent, it remains less than one-tenth of 1 1 percent. But by enough time a female reaches 40, her probability of developing breast malignancy in the next 10 years is 1.45 percent, or 1 in 69. A 20 percent boost raises her risk to 1 1.74 percent, or 1 in 57.

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Women who all stayed on hormones for 10 or even more years experienced a good 38 percent increase in their relative risk of developing breast malignancy, weighed against nonusers. By comparison, there was no elevated risk for breast cancer seen in ladies who applied hormones for under one year.

In Denmark, older women who have finished their families are most likely to use I.U.D.’s, including those containing hormones, and they are already even more likely to build up breast cancer as a result of how old they are, Dr. Mørch said.

“Nothing is risk-free, and hormonal contraceptives are not an exception compared to that rule,” said Dr. Øjvind Lidegaard, the paper’s senior writer. But he recommended doctors remember to discuss the professionals and cons of various kinds of contraception with their individuals, and that they be frank about the potential risks, suggesting ladies reassess hormone use as they age.

The study was supported by a grant from the Novo Nordisk Foundation, which describes itself as “an independent Danish foundation with corporate interests,” helping medical research at public institutions and by companies within the Novo Group. (Novo Nordisk is a global healthcare company that focuses on diabetes care, and it also makes Vagifem, topical estrogen inserts designed for menopausal women.)

A postscript with the article noted that two of the study’s authors, including Dr. Mørch, have already been utilized by Novo Nordisk because the manuscript was recognized for publication.

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