Endometrial cancer
In postmenopausal women, continuous combined estrogen plus progestin decreases endometrial cancer incidence. The duration of progestogen therapy should be at least 14 days per cycle to prevent endometrial disease.Endometrial cancer has been grouped into two forms in the context of hormone replacement. Type 1 is the most common, can be associated with estrogen therapy, and is usually low grade. Type 2 is not related to estrogen stimulation and usually higher grade and poorer in prognosis. The endometrial hyperplasia that leads to endometrial cancer with estrogen therapy can be prevented by concomitant administration of progestogen. The extensive use of high-dose estrogens for birth control in the 1970s is thought to have resulted in a significant increase in the incidence of type 1 endometrial cancer.Paradoxically, progestogens do promote the growth of uterine fibroids, and a pelvic ultrasound can be performed before beginning HRT to make sure there are no underlying uterine or endometrial lesions.Androgens do not stimulate endometrial proliferation in post menopausal women, and appear to inhibit the proliferation induced by estrogen to a certain extent.There is insufficient high‐quality evidence to inform women considering hormone replacement therapy after treatment for endometrial cancer. Breast cancer
Studies regarding the association of breast cancer with hormone replacement are inconsistent and vary with type of replacement and time since menopause. While some evaluations suggest an increased risk, in others it is decreased.
Society and public perception
Wyeth controversy
Wyeth, now a subsidiary of Pfizer, was a pharmaceutical company that marketed the HRT products Premarin (CEEs) and Prempro (CEEs + MPA). In 2009, litigation involving Wyeth resulted in the release of 1,500 documents that revealed practices concerning its promotion of these medications. The documents showed that Wyeth commissioned dozens of ghostwritten reviews and commentaries that were published in medical journals to promote unproven benefits of its HRT products, downplay their harms and risks, and cast competing therapies in a negative light. Starting in the mid-1990s and continuing for over a decade, Wyeth pursued an aggressive "publication plan" strategy to promote its HRT products through the use of ghostwritten publications. It worked mainly with DesignWrite, a medical writing firm. Between 1998 and 2005, Wyeth had 26 papers promoting its HRT products published in scientific journals.These favorable publications emphasized the benefits and downplayed the risks of its HRT products, especially the "misconception" of the association of its products with breast cancer. The publications defended unsupported cardiovascular "benefits" of its products, downplayed risks such as breast cancer, and promoted off-label and unproven uses like prevention of dementia, Parkinsons disease, vision problems, and wrinkles.