Aromatase inhibitors ( AIs)、especially three third generation AIs, have become the gold-standard for endocrine therapy of estrogen receptor ( ER) positive early and advanced breast carcinoma for postmenopausal women. However, some questions on this treatment still remain unanswered. For example, whether patients should initiate an aromatase inhibitor at the onset of hormonal therapy or use the early sequencing approach by using Tamoxifen and AI?. BIG 1 98 study published in New England Journal of Medicine 2009 could provide important information on the relative benefits and risks of those 2 approaches. Another issue is about the optimal duration of aromatase inhibitor therapy. This will be addressed by an MA.17 extension trial as well as a trial being activated by National Surgical Adjuvant Breast and Bowel Project B 42. However, the overall survival benefit of extended therapy is only limited in lymph node positive breast cancer patients .At least further 4 years of aromatase inhibitor treatment after the first 5 years of adjuvant tamoxifen is recommended in postmenopausal endocrine responsive early breast cancer, nowadays. The value of extended tamoxifen therapy is still controversial, though it might be of interest especially in premenopausal patients. Tailoring treatment according to risk of disease recurrence, patient life expectancy, comorbidity, risk factors for cardiovascular disease or osteoporosis and compliance is necessary.

　　The additional question is how to treat the lymph node negative patient? Is there any role for interrupted AI therapy in extended strategy? Another issue is regarding the three AIs. Is there significant difference between steroid and non-steroidal AIs in terms of efficacy and adverse effect? Whether all patients should receive an aromatase inhibitor or whether some subgroups of patients might be optimally treated by tamoxifen alone is yet to be established. Do we need to check the CYP2D6 polymorphism before tamoxifen use? Do concomitant use SSRI will compromise the tamoxifen efficacy?

　　In premenopausal patients, suppression of ovarian function and the use of tamoxifen are the most important therapeutic options, even though questions on timing, duration, and combination of these compounds remain unanswered. What’s the clinical significance of chemo-induced amenorrhea? The use of aromatase inhibitors in combination with ovarian-function suppression is currently under investigation in the premenopausal setting.

　　Otherwise, nodal status should no longer dictate adjuvant chemotherapy, in other words, tumor biology should play more role while making decision in choice adjuvant therapy. Thus, complete hormonal therapy seems a good option especially in luminal A and even some luminal B premenopausal breast cancer patient. However, the optimal adjuvant endocrine strategy for a patient has to be evaluated by individual consideration, taking into account the expected benefits and toxic effects of each treatment option. The future role in molecular biology could help us to define who might benefit from which endocrine therapy strategy.