Follow-up study discovers use of hormone replacement drugs leads to more advanced and fatal cancers.
Hormone treatment after menopause was originally studied by the Women’s Health Initiative (WHI) as part of a clinical trial established in 1992 to assess its relationship to coronary heart disease. Those studies were halted in 2002 when the results indicated that women taking a combination of estrogen and progestin had a higher risk of heart disease, stroke, and invasive breast cancer when compared to women taking a placebo. Now, a new study published October 20, 2010 in the Journal of the American Medical Association (JAMA) reports that these breast cancers associated with hormone treatment are more aggressive, more advanced, and have a higher mortality rate.
The WHI continued to follow the women with breast cancer after the main trial had ended. Some earlier observational studies had suggested that hormone therapy induced breast cancers were less advanced and had a lower risk of death. However, this new WHI finding strongly contradicts those suggestions. Combined hormone therapy increased the incidence of invasive breast cancer and in many cases the cancer had spread to the lymph nodes making it a more deadly form of cancer. Most significantly, it was found that the use of hormone therapy made the detection of breast cancer more difficult resulting in the cancer being diagnosed at a more advanced stage.
For many years, menopausal women were treated with a combination of drugs to treat hot flashes and mood swings. Premarin, manufactured by Wyeth, contained estrogen, while Provera, manufactured by Pfizer’s Pharmacia and Upjohn, contained progestin. In 1995, Wyeth combined the two hormones to form the medication, PremPro. Following the initial findings of the WHI in 2002 that linked estrogen and progestin to increased incidences of breast cancer, sales decreased dramatically. Sales of Premarin and PremPro were approximately $213 million in 2009, down from almost $2 billion prior to 2002.