October 19, 2010
A study has shown that postmenopausal women who take Hormone Replacement Therapy (HRT) have increased cases of breast cancers, breast cancers that are more aggressive and have twice the risk of dying from the disease than women taking a placebo.
The study entitled Estrogen Plus Progestin and Breast Cancer Incidence and Mortality in Postmenopausal Women appears in the October 20, 2010 issue of The Journal of the American Medical Association JAMA.
Study researchers conducted an eleven-year follow-up of 12,788 participants of the Women’s Health Initiative trial of estrogen plus progestin.
The Women’s Health Initiative (WHI), launched in 1991, consisted of a set of clinical trials and an observational study, which together involved 161,808 generally healthy postmenopausal women. One WHI trial was the Postmenopausal Hormone Therapy Trial of estrogen plus progestin. However, WHI stopped this trial in 2002 after investigators found that the increased risks of heart attack, stroke, blood clots and breast cancer associated with the combination hormone therapy outweighed the benefits.
According to the study, women taking the HRT estrogen plus progestin had more incidences of breast cancer compared to women taking a placebo (385 cases vs. 293 cases), and the cancers were more commonly node-positive (81 cases vs. 43 cases). Node-positive is a term used to describe a breast cancer that has spread to the lymph nodes, an indication of a more aggressive cancer.
Twice as many women taking HRT died of breast cancer than those taking the placebo.
Names of estrogen plus progestin combination HRT medications:
- Activella® (containing Estradiol, Norethindrone)
- Angeliq® (containing Drospirenone, Estradiol)
- FemHrt® (containing Ethinyl Estradiol, Norethindrone)
- Mimvey® (containing Estradiol, Norethindrone)
- Prefest® (containing Estradiol, Norgestimate)
- Premphase® (containing Conjugated/Equine Estrogens, Medroxyprogesterone)
- Prempro® (containing Conjugated/Equine Estrogens, Medroxyprogesterone)
Pfizer released a statement responding to the study.
“As to its risks, hormone therapy is among the most thoroughly studied medicines and the increased risk of breast cancer compared to placebo has been included in Prempro’s label since its introduction in 1995,” said pharmaceutical giant Pfizer Inc. regarding its HRT drug Prempro in response to the JAMA article. “This analysis does not alter that risk, nor does it dispute hormone therapy’s effectiveness. FDA describes hormone therapy as ‘the most effective FDA approved medicine for relief of hot flashes [and] night sweats.’ We stand behind the current, science-based guidance in Prempro’s label, which advises doctors to prescribe the medicine at the ‘lowest effective dose and for the shortest duration consistent with treatment goals and risks for the individual woman’ and patients to ‘talk regularly’ with their healthcare provider about whether treatment is still appropriate for them.”
Bloomberg Businessweek reports that Prempro, which Pfizer acquired in purchasing Wyeth, had annual sales of more than $2 billion before the WHI study halted in 2002 and use of HRT drugs declined.