If HRT is necessary after breast cancer, estrogen-only therapy or estrogen therapy with a progestogen may be safer options than combined systemic therapy. In women who are BRCA1 or BRCA2 mutation carriers, HRT does not appear to impact breast cancer risk. The relative number of women using HRT who also obtain regular screening mammograms is higher than that in women who do not use HRT, a factor which has been suggested as contributing to different breast cancer detection rates in the two groups.With androgen therapy, pre-clinical studies have suggested an inhibitory effect on breast tissue though the majority of epidemiological studies suggest a positive association. Ovarian cancer
HRT is associated with an increased risk of ovarian cancer, with women using HRT having about one additional case of ovarian cancer per 1,000 users. This risk is decreased when progestogen therapy is given concomitantly, as opposed to estrogen alone, and also decreases with increasing time since stopping HRT. Regarding the specific subtype, there may be a higher risk of serous cancer, but no association with clear cell, endometrioid, or mucinous ovarian cancer. Hormonal therapy in ovarian cancer survivors after surgical removal of the ovaries is generally thought to improval survival rates. Other malignancies
Colorectal cancer
In the WHI, women who took combined estrogen-progesterone therapy had a lower risk of getting colorectal cancer. However, the cancers they did have were more likely to have spread to lymph nodes or distant sites than colorectal cancer in women not taking hormones.
Route of administration
The medications used in menopausal HRT are available in numerous different formulations for use by a variety of different routes of administration:
Oral administration – tablets, capsules
Transdermal administration – patches, gels, creams
Vaginal administration – tablets, creams, suppositories, rings
Intramuscular or subcutaneous injection – solutions in vials or ampoules
Subcutaneous implant – surgically-inserted pellets placed into fat tissue
Less commonly sublingual, buccal, intranasal, and rectal administration, as well as intrauterine devicesMore recently developed forms of drug delivery are alleged to have increased local effect lower dosing, fewer side effects, and constant rather than cyclical serum hormone levels. Transdermal and vaginal estrogen, in particular, avoid first pass metabolism through the liver. This in turn prevents an increase in clotting factors and accumulation of anti-estrogenic metabolites, resulting in fewer adverse side effects, particularly with regard to cardiovascular disease and stroke.Injectable forms of estradiol are no longer recommended in menopausal hormone therapy due to the availability of other formulations. Bioidentical hormone therapy
Bioidentical hormone therapy (BHT) is the usage of hormones that are chemically identical to those produced in the body. Although proponents of BHT claim advantages over non-bioidentical or conventional hormone therapy, the FDA does not recognize the term bioidentical hormone, stating there is no scientific evidence that these hormones are identical to their naturally occurring counterparts. There are, however, FDA approved products containing hormones classified as bioidentical.Bioidentical hormones can be used in either pharmaceutical or compounded preparations, with the latter generally not recommended by regulatory bodies due to their lack of standardization and regulatory oversight.