Breast Cancer Incidence Dramatically Declines as Hormone Therapy (HT) Use Decreases

By: Red Hot Mamas

Published: May 26, 2010

The hormone therapy debate continues! The latest scoop to hit the press brings some interesting findings on breast cancer and its possible relationship to hormone therapy.

According to the most recent population statistics, the incidence of breast cancer in the United States plummeted in 2003. Researchers suggest the dive was the result of women discontinuing hormone therapy after Women’s Health Initiative results were released in 2002.

In December, scientists at the University of Texas MD Anderson Cancer Center in Houston presented the numbers at a breast cancer conference. Information from the National Cancer Institute on breast cancer incidence revealed a seven percent drop (about 14,000 cases) in 2003.

The trends until1998 show a slow rise in breast cancer incidence. Then, rates decreased by 1% per year from 1998 to 2003. The drop by 7% in 2003 was a contrast to the previous years.

Today, with the new numbers about breast cancer available, some researchers suggest the trend was a result of millions of women discontinuing hormone therapy after the Women’s Health Initiative (WHI) results were released.

The Women’s Health Initiative (one of the largest US prevention studies) was halted in July, 2002. Researchers found that women taking hormone therapy had slightly (but not significantly) higher breast cancer rates. Approximately half of the women who were on hormone therapy went off their treatment in the months that followed.

The downward trend of breast cancer incidence in 2003 was most pronounced among women between the ages of 50 and 69 (exactly the group who is most likely to be on hormone therapy). The decline was also significant for a specific type of breast cancer called estrogen receptor-positive tumors (accounting for 70 percent of all breast cancers).

Look at the Possibilities

Some professionals feel as if the cessation of hormone therapy may not account for the breast cancer decline. Many think there are other variables involved in the story. The lag time between the marked decline in HT prescriptions (after the WHI halted in 2002) to the instance we saw a dive in breast cancer rates (a year and a half later) was short. Some think it was too short a time period for breast cancer to develop to a detectable stage (where it can be seen in a mammogram).

“There are several factors that have contributed to what I think will unfortunately only be a very temporary decline,” says Mary Jane Minkin, MD, a medical advisor of the Red Hot Mamas. “First of all, if a woman doesn’t have to see her ob/gyn for a prescription of hormone therapy, she may postpone her exam (usually physcians prescribe a yearly supply). So, if she has no impetus to show up at her doctor’s office in exactly a year, she may not.”

Dr. Minkin continues, “Let’s look at a woman who received her year’s supply of pills in May 2002, had her mammogram in June 2002, and stopped her pills in July 2002 (during the WHI scare). She may not bother to see her ob/gyn for well over another year. She would normally have seen her doctor for her annual in June 2003, but said, ‘why bother’. Therefore, she didn’t get a requisition for her mammogram, and may not have had her yearly mammogram for well over a year, possibly in January 2004, after the holidays. It’s a reasonable scenario, and if she had developed an abnormal mammogram, it wouldn’t be picked up on her annual exam because, she didn’t have one.”

Scientists already know that hormones (estrogen and progestin) can increase the growth of estrogen positive tumors. And, if the tumors do not get the hormones they need to grow, they will stop growing.

“Estrogen and progestin promote the growth of already extant breast cancer. The enhanced promotion of growth would have ceased for women who already had small breast cancers prior to July 2002 and who were exposed to HT in July 2002,” explains Dr. Minkin.

“These women would have slowed (not stopped) the growth of their tumors, and the length of time for detection of the tumors would lengthen (which is why eventually you’ll see them, but just not immediately).” Dr. Minkin hypothesizes, “I think if you follow folks long enough, you will unfortunately see a return to the increasing rates.”

The North American Menopause Society also released comments from Leon Speroff, MD, Francine Grodstein, ScD, and Mergery Gass, MD in their First to Know newsletter. They offer other possible explanations for the decline and stress that the nature of this particular study cannot prove causality. For more information about their comments, log onto

To Be Continued…

Many questions still remain. Will we see the same patterns when other countries (like Europe or Canada) examine similar statistics? In the USA, 2004 data will be released in the spring of next year. We will then have the opportunity to see if the declining rates have persisted.

Overall, we will gain a better insight on the possible association between HT and breast cancer incidence by gathering data from multiple studies over a few years and across several countries. Further analyses are necessary to confirm the suggestion that HT caused the decline.

Before you hold your breath for the next hormone therapy news bulletin and before you abandon your HT regimen, talk to your healthcare provider. Each woman is different; therefore no “one size fits all” solution exists.

Many women will benefit from hormone therapy for the relief of menopausal symptoms. The current recommendation for those who are using hormone therapy to relieve menopausal symptoms is to use the lowest dose for the shortest duration of time.

Additionally, non-hormonal prescribed products and complementary and alternative approaches also relieve menopausal symptoms. Be aware that the safety and efficacy of these products has not always been proven. It is important to discuss these options with your physician.

Log onto the North American Menopause Society