Why is targeted therapy administered once every 21 days?

Targeted therapy is not necessarily performed every 21 days. Specific details are as follows:

Targeted therapy refers to the use of targeted drugs to treat certain malignant tumors. Most targeted drugs can accurately identify tumor cells and destroy them through various mechanisms, thereby killing tumor cells while minimizing damage to normal cells. This type of therapy is characterized by relatively mild side effects and good efficacy, making it suitable for patients with occult onset and rapidly progressing tumors. The frequency of targeted therapy depends on individual circumstances. For example, breast cancer patients receiving pertuzumab and trastuzumab typically undergo treatment every 21 days. However, lung cancer patients, who mostly receive drugs such as gefitinib or erlotinib, usually undergo treatment every 28 days.

If targeted therapy is required, it is recommended to seek treatment at a reputable hospital. Patients with poor physical condition may experience gastrointestinal discomfort, bone marrow suppression, or other adverse reactions during treatment and might not tolerate the therapy well. Additionally, patients should select the appropriate targeted drug according to their specific condition under the guidance of a physician.