Hormone Therapy & Trends in Breast Cancer Incidence
Posted Jan 12 2010 12:00am
Recent breast cancer research studies have reported that breast cancer rates have been declining, which is great news. However, the reasons for this decline in breast cancer is uncertain, generally being attributed to improvements in breast cancer screening or reductions in the use of menopausal hormone replacement therapy that occurred after the publication of the Women's Health Initiative study. A new breast cancer research study published just a few days ago and free to download looked more closely at the relationship between breast cancer incidence and hormone therapy use.
In their study, researchers used data from the California Teachers Study to investigate changes in hormone therapy use and breast cancer incidence among nearly 75,000 women 50 years of age or older. Hormone therapy use was classified as 'never', 'past', or 'current' according to questionnaires completed in 1995-1996 and in 2000-2001. The research investigators reported:
75% of women reporting estrogen-progestin therapy use and 58% of women reporting estrogen-only therapy use in 2000-2001 had stopped hormone therapy use by 2005-2006.
Irrespective of hormone therapy use, rates of invasive breast cancer dropped by 26% between 2000-2002 and 2003-2005 with a 25% drop in ER-positive breast cancer and a 14% drop in ER-negative breast cancer.
Rates of invasive breast cancer were relatively stable for women who were 'never' or 'past' users of hormone therapy; however, women classified as 'current' estrogen-progestin hormone therapy users at the beginning of the study showed a 46% decline in breast cancer from 2000-2002 to 2003-2005.
Breast cancer rates dropped by nearly 40% in women who stopped hormone therapy use by 2000-2001.
The decline in breast cancer in this population of women was most likely due to a decline in hormone therapy use because most of the women were hormone therapy users at some time in the past and the majority of the hormone therapy users had stopped by 2005.
While breast cancer screening is vitally important for discovering breast tissue changes and catching breast cancer early, this study suggests that the greatest reason for the recent decline in breast cancer incidence is the decline in the use of hormone therapy, particularly estrogen-progestin therapy. Previous studies have reported similar results, but this current study appears to have a greater level of information on individual use of hormone therapy, making the argument against hormone therapy use more compelling. The U.S. FDA recommends that menopausal hormone therapy be used at the lowest doses for the shortest duration to reach treatment goals. You can learn more about the risks and benefits of menopausal hormone therapy in the National Institute of Health's fact sheet.
In addition to following appropriate guidelines for hormone therapy use, there are many other easy changes you can make to reduce your breast cancer risk. To learn more, read my book Fight Now: Eat & Live Proactively Against Breast Cancer at www.fightBCnow.com.