Neoadjuvant therapy is currently the standard treatment process for locally advanced breast cancer, especially for human epidermal growth factor receptor 2 (HER2) positive and triple negative breast cancer, which meets the requirements of tumor ≥ 2cm and/or lymph node positive, and the guidelines recommend neoadjuvant therapy as the first choice. Chemotherapy combined with trastuzumab and pertuzumab is the standard neoadjuvant therapy for HER2 positive breast cancer patients. Taxane plus carboplatin (TCb) is the first choice of chemotherapy recommended by major guidelines; As an alternative, single drug Taxane (T) is also listed as class I recommendation in the latest CSCO guidelines, but the level of evidence is slightly insufficient. Considering the defects such as large side effects of combined chemotherapy, whether single drug chemotherapy can be used as the first choice for some people under the support of targeted drugs remains to be studied.

This project plans to a cohort study, based on the large sample breast disease cohort database established by the breast center of Peking University People's Hospital, and retrospectively include the patients with clinical stage T2 and above and/or lymph node positive breast cancer who received neoadjuvant therapy (TCbHP or THP) from January 1, 2015 to December 31, 2024. Patients of the same type were prospectively included from January 1, 2025 to December 31, 2028. The effectiveness and safety of TCbHP and THP as a neoadjuvant therapy were compared.

Inclusion Criteria:

• 1) Patients with HER2 positive breast cancer diagnosed by biopsy in Peking University People's Hospital;
• 2) The clinical stage was stage II or stage III (i.e. T2 and above, and/or lymph node positive, without distant organ metastasis);
• 3) Received treatment in our hospital and had hospitalization records;
• 4) Has signed and agreed to participate in the PKUPH breast disease cohort study.

Exclusion Criteria:

• 1) Lack of clinical and pathological data (such as imaging data and pathological data);
• 2) Patients with metastatic breast cancer or bilateral breast cancer;
• 3) At the same time, they received anti-tumor therapy in other clinical trials, including endocrine therapy and targeted therapy;
• 4) Receiving other regimens besides the established neoadjuvant regimens

HER2 positive breast cancer patients who received neoadjuvant chemotherapy based on taxanes with trastuzumab, pertuzumab target therapy