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By Vivian Richardson, Ivanhoe Health Correspondent
ORLANDO, Fla. (Ivanhoe Newswire) -- Premenopausal women who take oral contraceptives have an increased risk of breast cancer, according to a new analysis of a decade of research.
Lead author Chris Kahlenborn, M.D., from Altoona Hospital in Altoona, Penn., extracted data from 34 studies to come up with his findings. He told Ivanhoe 21 out of 23 retrospective studies suggested women who took oral birth control before having their first child have a 44-percent increased risk of developing breast cancer.
"What's scary about is that no one has really heard about it until now, and it's been in the literature for the last decade," said Dr. Kahlenborn, who has also written about the link between abortion and oral contraceptives.
The estimated risk for breast cancer in the general population is about one in eight over a lifetime, according to the National Cancer Institute. A 44-percent increase of this risk would equal out to about one in five, but Dr. Kahlenborn says it's too soon to judge whether the increased risk associated with oral contraceptives will last over a lifetime.
Dr. Kahlenborn says many women do not know about all the risks associated with hormonal birth control, and the medical community is partly to blame.
"There's tremendous vested interested -- drug companies with a lot of money, government agencies who give a lot of money for contraception. It doesn't make people look good when a study like this comes out," he said.
Length of contraceptive use did not have an affect on the risk level for women who had not had children yet. Among women who have had children, however, use of oral contraceptives for more than four years did increase their risk over those who used them for a shorter duration.
The increased risk of breast cancer is probably the same or higher with other forms of hormonal birth control, like the patch, rings, or IUDs with hormones, according to Dr. Kahlenborn.
"I would expect a higher risk, but a lot of these things just came out five years ago. And what the companies will say is there is not much increased risk because it takes 40 years," he said. "Like with the pill, we're hearing about this now? This was invented in 1960, and here we are in 2006, and that's 46 years to hear about this?"
Dr. Kahlenborn is an internist and doesn't usually work on family planning with his patients. He does, however, recommend the Billings method when his patients ask. This method is based on changes in cervical mucus when a woman is fertile. When women recognize a change in their natural lubrication, they know they are close to ovulation and it's possible they will conceive if they have sex.
In an editorial accompanying Dr. Kahlenborn's study, James Cerhan, M.D., from the Mayo Clinic of Epidemiology in Rochester, Minn., raises a few questions about this research. While he agrees the evidence shows there is some kind of link between breast cancer and contraceptives, he writes all risks and benefits of oral contraceptives must be weighed against one another.
This article was reported by Ivanhoe.com, who offers Medical Alerts by e-mail every day of the week. To subscribe, go to: http://www.ivanhoe.com/newsalert/.
SOURCE: Ivanhoe interview with Chris Kahlenborn, M.D., Altoona Hospital, Altoona, Penn.; Mayo Clinic Proceedings, 2006;81:1290-1302:1287-2189
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