Thursday, April 19, 2007

Sharp Drop in Rates of Breast Cancer Holds

Breast cancer rates fell sharply in 2003, and the lower rate remained in 2004, researchers are reporting today. The finding, they say, fits with a hypothesis they advanced last December when they had data only from 2003. At that time, national data showed that breast cancer rates fell by nearly 15 percent in the 18 months from July 2002 through December 2003. The most likely reason for the fall in rates, the investigators, led by Donald A. Berry of M. D. Anderson Cancer Center in Houston, said, was that large numbers of women stopped taking hormone therapy for menopause. And that therapy, a combination of estrogen and progestins, can increase the incidence of breast cancer. Now, with the 2004 data, the researchers say the effect is less likely to be an anomaly. If rates had gone up again, they explain, it would have meant that their hypothesis was incorrect, according to the paper published today in The New England Journal of Medicine. Over all, in 2003 and 2004, there were nearly 10 percent fewer breast cancer cases than expected. It is the first substantial drop in breast cancer incidence in more than a quarter century.

The hormone connection came because the Women’s Health Initiative, a large federal study examining the health effects of Prempro, the most popular drug prescribed for menopause, was halted in July 2002. The study found that women taking Prempro had an increased risk of heart disease, rather than protection from it. In addition, there was more breast cancer among women taking Prempro than those taking a placebo for comparison. Immediately, sales of Prempro, made by Wyeth, plummeted, falling by 50 percent, and they continued to fall slightly in 2004. The drop in breast cancer followed immediately. “Those are the facts,” said Dr. Peter Ravdin, an oncologist and Dr. Berry’s colleague. “We think there is a likely connection between them.” Any alternative explanation must also take into account the fact that the drop in breast cancer rates was almost entirely estrogen-fed tumors, Dr. Ravdin said. Dr. Berry said the researchers were well aware of the limitations of their analysis and never said they proved that declining hormone use led to 10 percent less breast cancer. “Of course, we’re not sure. We never are,” Dr. Berry said. “But it fits. It’s a smoking gun.”

Courtesy of the New York Times

Bonnie - there has been a resurgence of talk touting the safety of synthetic hormone therapy in younger women. After reading this and a recent Lancet study linking synthetic hormones to ovarian and breast cancer, I cannot see how one would want to take a chance.

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