To Your Health
What's Behind the Drop in Breast Cancer Rates?


by Paulette Avery RN, MSN, IBCLC


A few weeks ago the media ran headlines such as, "Fewer breast cancer cases linked to less hormone therapy" (Reuters, December 14); and, "Breast cancer drop tied to hormones" (Yahoo News, December 15). I, like many of you, jumped on the bandwagon, assuming the drop in breast cancers was a result of fewer women using hormone replacement therapy (HRT) for the past few years. But the story is not as simple as what was presented to us by the media and is a reminder to look deeper into the health headlines.

The headlines came from reports at the 20th San Antonio Breast Cancer Symposium, held in December. According to a press statement from the International Menopause Society (IMS), a report from the Kaiser Permanente Division of Research and the Northern California Cancer Center showed an "11 percent difference in the rate of breast cancer between 2001 and 2003" for women between the ages of 50 and 74. A similar drop in breast cancer was also reported by the M.D. Anderson Cancer Center at the University of Texas. Their data indicate an overall drop of eight percent in breast cancer and a drop of 12 percent in women aged 50-69 diagnosed with estrogen receptor-positive cancer from 2001 to 2003.

After a report in 2002 that the benefits of taking HRT did not outweigh the risks, thousands of women stopped taking hormones to treat the symptoms of menopause. It seems logical that there may be a link between that fact and the drop in breast cancer. "However," says the International Menopause Society's statement, "any attempt to link both into one framework is premature, and the scientific basis for such an assessment has not been established." Likewise, comments in a special issue of the North American Menopause Society's newsletter state, "Because the analysis was based solely on population statistics, the reasons why incidence declined is not certain."

Here are some of the factors to consider about this issue. First, what happened to the rate of women getting mammograms during the same time period? It could be that many women who stopped taking hormones also stopped seeing their doctors as often and, as a result, had fewer mammograms. If so, the decline in breast cancer could be the result of fewer cases of breast cancer being diagnosed.

Second, a look at other related statistics does not support the link between the drop in breast cancers and the lower usage of HRT. Some decrease in breast cancer rates was already apparent from 1999-2001, and a similar decrease in breast cancer has not been found in other countries. There was also a drop in the type of breast cancers not linked to hormones. Also, consider that it is unlikely that such a large drop in cancers would occur within such a short time after hormone usage was stopped.

Some experts say the drop more likely reflects an effect on existing cancers that slowed their growth or stopped growing when women stopped taking hormones. How the rates will be affected in coming years remains to be seen.

"The IMS maintains its recommendation that hormone therapy should be prescribed whenever indicated. The use of hormones in early menopause and up to age 60 years has a very minor potential for harm, but may carry substantial benefits." Finally and maybe most important, it is great news that the rate of breast cancer has declined. May it continue to do so!

Paulette Avery is a registered nurse and a freelance writer who specializes in health care issues.