Breast cancer patients do not have to take Letrozole for life, clinical Letrozole is mainly used for postoperative endocrine treatment of breast cancer, its standard taking time is 5 years, if the condition requires, you can extend the taking time. Letrozole is an anti-tumor drug that can effectively eliminate the stimulating effect of estrogen on tumor growth, and is the drug of choice for endocrine therapy for postmenopausal breast cancer patients, and the time of use of the drug varies according to the condition. For early-stage breast cancer patients, the standard duration of letrozole is 5 years, which can be extended to 10 years if the condition is serious, such as those at high risk of recurrence, while advanced breast cancer patients can continue to use it until it is intolerable or the condition worsens. Side effects of Letrozole mainly include nausea, headache, arthralgia, fever, hyperlipidemia, hypertension, palpitations (rapid heartbeat, often accompanied by panic), vaginal bleeding, etc., which should be closely monitored and followed up with checkups during the period of taking the drug. The prohibited groups of Letrozole include premenopausal, pregnant and lactating women and those who are allergic to any components of Letrozole. It is recommended that breast cancer patients should take the drug strictly according to the doctor’s instruction and regular review, and should not take the drug or stop taking the drug on their own to avoid adverse consequences.