Yes. Researchers are currently looking at substances called aromatase inhibitors that might also help reduce risk. Aromatase inhibitors prevent the formation of estradiol, which is a female hormone. Women who are post-menopausal and whose breast cancer is hormone-dependent may respond well to this therapy.  New research shows women with early-stage breast cancer who took the drug letrozole, an aromatase inhibitor, after they completed five years of tamoxifen therapy significantly reduced their risk of breast cancer recurrence.  Also, other new research found a test that can predict both the risk of breast cancer recurrence and who is most likely to benefit from chemotherapy such as letrozole.  Another study, known as TAILORx, was launched by the National Cancer Institute in May 2006, to examine whether genes that are frequently associated with risk of recurrence for women with early-stage breast cancer can be used to assign patients to the most appropriate and effective treatment.