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Results may trouble women on birth control pill

Whether women currently taking birth control pills have a higher risk of breast cancer has long been a matter of debate with some studies suggesting that they do, and others suggesting that they don’t. But a new finding is certain to give some pill takers, like myself, pause.

Researchers from the Fred Hutchinson Cancer Research Center in Seattle examined medical records from more than 1,100 breast cancer patients ages 20 to 49 and found that those taking oral contraceptives within a year of their diagnosis had a 50 percent higher risk of getting the cancer compared with healthy counterparts of the same age who weren’t taking the pill.

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More concerning, those taking formulations with high levels of estrogen — 50 micrograms or more of ethinyl estradiol per pill — had a nearly three times greater risk of developing breast cancer, according to the study published in the journal Cancer Research. Triphasic pills containing an average of 0.75 mg of norethindrone, a synthetic form of progesterone, also were associated with this higher risk. On the other hand, women taking pills with low-dose estrogen — 20 micrograms of ethinyl estradiol — didn’t have a higher breast cancer risk.

“We are interpreting our results cautiously,” said study leader Elisabeth Beaber. “These are initial findings that need to be replicated before anyone can make clinical recommendations to women in terms of choices.”

What’s more, the average woman’s risk of getting breast cancer before age 50 is very small, less than 1 percent over a five-year period — so even a doubling or tripling of risk while she’s taking the pill isn’t that significant.

That didn’t stop me from looking at my pill formulation: It contains 20 micrograms of estrogen and is not triphasic, which means each pill with active ingredients contains the same amount of hormones.

While my worries were assuaged a bit, I wondered whether taking oral contraceptives continuously for the past 14 years was going to lead to negative health consequences. Should I switch to a non-hormonal form of birth control?

A limitation of the latest study is that it didn’t survey participants to see how long they were taking the pill before their diagnosis.

“But other studies, looking at long-term use of the pill haven’t shown an association with a higher lifetime risk of breast cancer,” said Dr. Daniela Carusi, director of general gynecology at Brigham and Women’s Hospital. While women have an increased breast cancer risk while taking the pill, this risk drops down to normal within 10 years of stopping oral contraceptives.

Women taking higher-dose estrogen pills — such as Ortho-Novum 1/50, Ovral, or Ovcon 50 — may want to speak to their doctors about whether they need to be on such a high dose. Carusi said doses over 35 micrograms are rarely prescribed, but some women, such as those who are obese, may need a higher amount of estrogen to get full pregnancy protection.

Stacking up in favor of the pill: It’s good at protecting against unplanned pregnancies and research suggests it protects against uterine and ovarian cancer. The pill’s risks — which include blood clots, heart attacks, and strokes as well as breast cancer — do mount as a woman ages, especially if she smokes.

For healthy women, the pill’s benefits outweigh its risks at any age before menopause, Carusi said. Some women, however, need to take precautions. Smokers over the age of 35 should not be taking oral contraceptives because they have a much higher than average risk of developing dangerous blood clots.

Those with hypertension need to make sure it is under control before starting the pill, Carusi said, since they could be at higher risk of having a stroke. “Somen women’s blood pressure will go up when they start the pill,” she said, “so we need to watch them to make sure it’s not.”

Doctors often consider a wide range of other heart disease risk factors, including their age, diabetes status, and cholesterol level, and might not want to recommend the pill to those with a higher risk of heart disease.

Other forms of birth control are available for high-risk women including an IUD or sterilization for those who don’t want to have more children.

Deborah Kotz can be reached at dkotz@globe.com. Follow her on Twitter @debkotz2.
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