Breast Cancer Mortality Increased By Hormone Therapy
Posted Aug 17 2010 7:25am
Hormone replacement therapy was designed to aid women through the menopausal transition by reducing common menopausal discomforts like hot flashes and night sweats. The most common form of hormone replacement therapy consists of a combination of estrogen plus a progestin. The progestin used in hormone replacment therapy was used to suppress the possible negative effects of estrogen, particularly in regards to uterine cancer risk. However, the Women's Health Initiative study showed that estrogen + progestin hormone therapy has a number of negative health effects, including a 24% increase in breast cancer risk over about a 5 year period.
While it is clear that estrogen + progestin hormone therapy (HRT) increases breast cancer risk in postmenopausal women, the impact of hormone therapy on death due to breast cancer is less clear. A recent re-analyis of the Women's Health Initiative study examined the impact of HRT on breast cancer incidence and death over the full follow-up period (11 years on average). This study consisted of two distinct parts, a clinical trial of over 17,000 postmenopausal women and an observational trial of over 41,000 postmenopausal women. In the clinical trial, women were assigned to receive either a placebo or hormone therapy. The HRT in this trial was a combination of conjugated equine estrogens + the progestin medroxyprogesterone acetate, a popularly prescribed hormone therapy. In the observational trial, women were grouped according to their current HRT status as either estrogen + progestin users on non-users. The breast cancer researchers reported the following
HRT users were at a 25% increased risk of developing breast cancer. More women in the HRT group (385) developed breast cancer than in the placebo group (293).
Breast cancers in the HRT group were more likely to involve the lymph nodes.
Death specifically due to breast cancer was nearly twice as high in the HRT group compared to the placebo group, while the risk for death from any cause was about 50% higher in the HRT group.
HRT users were at about a 33% increased risk of dying from breast cancer.
The risk of death from any cause was increased in the HRT group by over 80%
This full-follow-up analysis of the WHI research data confirms the intial results that estrogen + progestin hormone therapy increases the risk of postmenopausal women developing breast cancer and additionally demonstrates that death due to breast cancer is increased in HRT users. Since the research suggests the progestin is the major contributor to the increased breast cancer risk seen in HRT users, some might think that removing the progestin would be a logical step. However, this puts many women at risk for uterine cancer. Therefore, a number of research studies are exploring the potential use of different progestins. While a couple of studies suggest that other progestins appear to increase breast cancer risk factors , one recent study suggests that some progestins might suppress breast cancer and breast cancer risk factors . However, some of these studies were done in animal models of breast cancer using the progestins alone, meaning that additional work will be needed before we know for sure if different progestins might be safe and effective as part of a combination HRT. In the meantime, it remains important to follow the FDA recommendation and use hormone therapy (if you chose to do so) at the lowest effective dose for the shortest period of time necessary.
Breast cancer awareness is an important part of our fight against breast cancer. Learning things to avoid and changes you can make to reduce your breast cancer risk is vital. My FREE book, Fight Now: Eat & Live Proactively Against Breast Cancer is a great way to enhance your breast cancer awareness.