Study: The Pill Is Not Linked to Cancer

A major new study examining the risk of breast cancer for the millions of women who have used birth control pills will have them breathing a sigh of relief.

The government research, considered the definitive study on the topic, involved more than 9,000 women and more African-American women than any other of its kind. Its finding: Regardless of when a woman started using the pill, how long she used it, or whether she had a family history of breast cancer, oral contraceptives did not increase her risk for breast cancer.

"The results of our study are very good news," says Polly Marchbanks, a scientist with the Division of Reproductive Health at the Centers for Disease Control and Prevention in Atlanta and lead author of the study. "Our study provides reassurance that oral contraceptives do not increase the risk of breast cancer."

The pill is one of the most popular forms of birth control, with about 80 percent of American women estimated to have used it at some point in their lives. But many had been anxious ever since a report, six years ago, linked the pill to an increased risk of breast cancer.

"Sometimes that anxiety comes in years later after they've been taking it and somebody in the family gets breast cancer and they begin to wonder, 'What did I do in the past that might affect my risk now?' " Dr. Kathy Heltzhouer, professor of epidemiology at the Bloomberg School of Public Health at Johns Hopkins in Baltimore, explained to ABCNEWS' John McKenzie.

The study appears in this week's issue of the New England Journal of Medicine.

Pill Is Not Risk-Free

Despite the encouraging finding and other health benefits associated with pill use, experts are quick to point out that using birth control pills is not risk-free. asked experts to discuss what the results of the current study mean for women, as well as the other risks and benefits related to oral contraceptive use.

What is the role of oral contraceptives in other cancers? Are they thought to increase or decrease the risk of developing any cancers?

It's quite clear now that the birth control pill confers important protections against two cancers: the most common gynecologic cancer in North America, which is endometrial cancer, and the deadliest kind of cancer, which is ovarian cancer. That information is clear and incontrovertible. There is some suggestion that long-term use of birth control pills may pose an increase in cervical cancer for some women infected with human papilloma virus or HPV. With appropriate Pap smear screening, there should essentially be no women dying of cervical cancer taking birth control pills. — Dr. David Grimes, vice president of biomedical affairs at Family Health International in Durham, N.C.

What complications or adverse reactions are associated with pill use?

Most side effects of oral contraceptives such as nausea, breast tenderness and menstrual changes are not serious health effects and most subside six months after stopping use. Most of the more complicated issues are relatively rare, including blood clots and other cardiovascular risks. Oral contraceptives also do not prevent against sexually transmitted disease such as HIV. — Polly Marchbanks, Ph.D., scientist with the Division of Reproductive Health, Centers for Disease Control and Prevention in Atlanta.

Are some women at greater risk for complications than others?

Clearly women who have an increased risk of cardiac disease [or stroke] — for example women who have hypertension — shouldn't take the pill. But we can screen folks like that to find very safe, appropriate candidates for pill taking. Women who smoke should be encouraged to quit smoking. Women who smoke and are 35 and older shouldn't take the pill because the risk becomes too great. The point is: The pill is safe, cigarettes are dangerous. — Dr. David Grimes, vice president of biomedical affairs at Family Health International in Durham, N.C.

Are certain formulations of the pill safer than others?

I think the literature is fairly secure now that the third-generation pills with these newer formulations of [the hormone] progestin probably increase the risk of blood clots slightly. The net public health impact is small because clots are very rare events in healthy young women, and they are rarely fatal. But if one is concerned about that, they have a whole array of other pills to choose from that do not include these progestins. — Dr. David Grimes, vice president of biomedical affairs at Family Health International in Durham, N.C.