The indirect comparison of
LHRH agonist with
tamoxifen showed similar efficacy in the adjuvant treatment of premenopausal endocrine-responsive
breast cancer patients. Furthermore,
LHRH agonist is as effective as
cyclophosphamide,
methotrexate and
5-fluorouracil chemotherapy. Data concerning combination of
LHRH agonist with third-generation
aromatase inhibitors are still lacking. Moreover,
duration of therapy with
LHRH agonist is still a matter of debate. In randomized clinical trials, each of the third-generation
aromatase inhibitors (AIs) has demonstrated efficacy in the adjuvant treatment of postmenopausal women with receptor' -positive
tumors.
Anastrozole has been shown to improve disease-free survival when compared with
tamoxifen,
letrozole has been shown to further reduce the rate of
breast cancer events when given as extended adjuvant
therapy in women completing between 4.5 and 6 years of
tamoxifen, and
exemestane has been shown to improve disease-free survival when substituted for
tamoxifen after an initial 2-3 years of adjuvant
therapy. Although long-term follow-up for safety and overall survival continues in each of these trials, currently available data suggest that an AI should now be included as part of adjuvant endocrine
therapy for the great majority of receptor-positive postmenopausal patients.