However, long-term effects are not yet known. At the moment, toremifene is only given to postmenopausal women. Tamoxifen is usually the first hormone therapy for advanced disease, but if the cancer does not respond to it there are several other options. Progesterones Progesterone is a hormone that occurs naturally in women. Artificial progesterone derivatives are stronger and are usually given by your doctor in tablet form or by injection.
Progesterone has very few side effects.
Although mild feelings of sickness may be a problem for a few women, most women find that progesterone increases their appetite. This may result in them putting on some weight, particularly in the stomach area. Some women also notice slight muscle cramps. A group of drugs called aromatase inhibitors work by blocking the production of oestrogen in fatty tissues, in women who have had the menopause. Aromatase inhibitors are an alternative to progesterones and are used to treat postmenopausal women whose breast cancer has stopped responding to tamoxifen.