Adjuvant endocrine therapy for breast cancer is currently the drug mainly TAM and third-generation AIs
(1) TAM
Pre-and post-menopausal patients with early breast cancer without ovarian removal or suppression of ovarian function, TAM is almost the only choice. However, the length of time on the TAM application, NSABP B14 research results have been shown to extend patients with lymph node-negative breast cancer TAM to 10 years, 5 years, compared with the medication did not show disease-free survival and overall survival advantage, but also led to the uterus endometrial cancer, cardiovascular and cerebrovascular diseases increased. However, the findings of recent ATLAS experiment showed different results. A total of 11.5 thousand cases of the trial in patients with early breast cancer were recruited to complete five years of adjuvant therapy after TAM, and then randomly assigned to TAM treatment and blank control groups, 10-year study found that 10-year recurrence rate of TAM treatment group, significantly lower than the control group, this advantage is not ER (+) or unknown, age, size, lymph node metastasis. The study also found that TAM after 5-9 years ,10-14-year period, this advantage persisted. Although the two groups no significant difference in mortality, but the mortality rate of 10-year low TAM group. The results of this study has not yet been a conclusion, but at least give us an indication of the patients with lymph node metastasis and prolong the time of medication TAM may still be a treatment option.
(2) The third-generation AIs
Post-menopausal breast cancer patients for adjuvant endocrine treatment options, the third-generation AIs has become an important treatment option, but its timing in the application there are a number of options to apply to a different patient populations, and these are followed as recommended programs permit medical support, has been written 2008 version of the NCCN breast cancer treatment guidelines. Concrete can be divided into the following three ways. First, from the outset regarding the use of AIs, to share for 5 years. The recommendation comes from ATAC, BIG-198 test results. The latest ATAC followed up for 100 months, the results show that anastrozole compared with TAM can improve disease-free survival rate of 4.8%, while BIG-198 followed up for 51 months, the results also showed that letrozole compared with 2.9% of the non-TAM disease free survival advantage. However, the overall survival rate of these two studies Anastrozole, Letrozole do not indicate the superior TAM. Therefore, we believe that due to the different AIs and TAM toxicity should be based on each patient’s condition and body condition, after a comprehensive measure of choice. For low-risk, medium risk patients, because AIs are not large in absolute returns, if the patients have osteoporosis, bone and joint disease and other diseases, side effects AIs associated, TAM may act as a treatment option. Second, in the tamoxifen use 2 ~ 3 years after the switch to AIs 3 ~ 2 years. Currently supports the above-mentioned clinical studies recommended, including switching to exemestane for IES031 test, switch to anastrozole for ITA testing and ARNO95 test. Third, in the five years of tamoxifen use, switch and extended the application of AIs 5 years. TAM currently supports five years after the switch and extend the application of AIs in clinical trials include the MA17 trial and NSABP B33 trial, the former support the re-switching and extend the application of five years of letrozole, which support the re-switching and extend the application of exemestane. This takes into account two kinds of patient populations, one is now taking TAM 2-3 years or have been applied TAM 5 years. The second is that the patient has entered the peri-menopausal period ,2-3 years of TAM, the patient is likely to enter the menopausal status, when the time switch to AIs logical.
As for the three kinds of third-generation aromatase inhibitors, which one better, is still a lack of randomized controlled comparative study of the results of ongoing anastrozole and exemestane compared MA27 trial, as well as anastrozole and letrozole The FACE trial will be given more looking forward to the answer.
