Herceptin refers to trastuzumab for injection, there is no fixed figure for what is the recurrence rate of breast cancer after using trastuzumab for injection, usually 10-30%. Trastuzumab for injection has adverse reactions and contraindications, and its use should be guided by a doctor. Trastuzumab for injection is suitable for the treatment of early breast cancer and metastatic breast cancer, and according to relevant studies, the recurrence rate of breast cancer after using trastuzumab for injection is between 10-30%. However, there is no accurate data on the recurrence rate of breast cancer using trastuzumab injection in China. Breast cancer itself is a kind of malignant tumor that is easy to recur and metastasize, and will recur under the influence of patient’s body resistance, pressure, psychological state, etc. If the treatment is not thorough and standardized, it will also cause breast cancer recurrence. Adverse reactions such as fever, vomiting, infection, cough, dyspnea, rash, nausea, etc. may occur after the use of trastuzumab injection for breast cancer. Trastuzumab is contraindicated in patients with known hypersensitivity to trastuzumab or to any of the other components of the product, and is prohibited for intramuscular injection in children. The use of trastuzumab for injection in patients with breast cancer should be directed by a physician and should not be used arbitrarily.