“New” Hormone Therapy and Breast Cancer Study

Don’t be surprised or blame your gynecologist if he or she had no information about the increased rate of breast cancer deaths associated with hormone use reported on Wednesday (October 20, 2010). One would think that physicians would get information before the media about new information and studies so we can appropriately and knowledgably respond to our patients' concerns, but unfortunately, that is not the case. The media gets the information before it is released to the public, which means your doctor gets information about a new study right about the time our phones start ringing. . 

So, when our phones started ringing yesterday my partners and I quickly got hold of the article to review the information.

Remember the Women’s Health Initiative (WHI) study released in 2002 that showed an increase in adverse outcomes in women taking estrogen and progesterone? The study that was later criticized since the average age of the woman in the study was 63, and 70% of the women in the study were over 60? The study that had much better outcomes when only women under the age of 60 were analyzed? The study that used an oral estrogen, which is rarely prescribed today and a progesterone that is known to be problematic? The study that only showed a slight increase in  breast cancer in the estrogen and progesterone group, not the estrogen-only group? The study that has very little to do with how we prescribe estrogen today? That study.

The new information looks back at an extension of the same flawed study with the frightening news that the risk of dying from an invasive cancer is dramatically higher in the group that took estrogen and progesterone.

If you look carefully at the numbers, it is not as significant as the screeching headlines make it sound.

Essentially, the study shows that there will be one to two extra deaths from breast cancer per 10,000 women per year. Specifically, for every 10,000 women in the study who were randomized to placebo (no hormones), there were 1.3 deaths from breast cancer per year. For every 10,000 women randomized to combined hormone therapy, there were 2.6 deaths from breast cancer per year. These results apply to women who took estrogen plus progestin and not to estrogen alone. Remember, the 2002 WHI found no increase in breast cancer risk with estrogen alone (without a progestin) among women with hysterectomy over an average of 7 years of randomized treatment.


The North American Menopause Society (www.menopause.org) stresses that the increased risk of breast cancer using estrogen plus progestogen for 5 years is very similar to the increased risk of breast cancer associated with having menopause 5 years later. This increased risk of breast cancer occurs with a woman’s own internal, natural estrogen and progesterone.

I am not minimizing the seriousness of breast cancer, or important information that is released from any study. But keep in mind that this information is unlikely to apply to you unless you started an oral estrogen and progesterone when you were more than 10 years after your last menstrual period.

For the woman who relies on a small dose of estrogen to think clearly, sleep and get through the day without flashing, there is no need to panic. If you are concerned, talk to your doctor, but based on this information there is no need to flush your estrogen down the toilet.

Added to Women's Health, Breast Cancer on Thu 10/21/2010