Use of estrogen antagonists and aromatase inhibitors in breast cancer and hormonally sensitive tumors of the uterine body

The new anti-estrogens, including the selective estrogen receptor modulators (e.g., toremifene, droloxifene, idoxifene, raloxifene and arzoxifene), the selective estrogen receptor downregulators (e.g., fulvestrant), and the new steroidal (e.g., exemestane) and non-steroidal (anastrozole and letrozole) aromatase inhibitors have been investigated in the treatment of breast cancer and hormonally sensitive tumors of the uterine body. In postmenopausal women, anastrozole, letrozole and exemestane appear to have superior efficacy and an improved toxicity profile than tamoxifen, and fulvestrant seems to be at least as effective as anastrozole in patients in whom tumors have progressed after prior endocrine treatment. Preliminary data showed a high response rate and a favorable toxicity profile for arzoxifene in endometrial cancer, whereas letrozole could represent a new interesting therapeutic tool for endometrial cancer as well as for low-grade endometrial stromal sarcoma.