The traditional neoadjuvant therapy for triple negative breast cancer is based on anthracycline, paclitaxel and carboplatin. Nowadays, immunotherapy combined with chemotherapy has become a new standard treatment, which not only benefits from pathological complete response (pCR), but also benefits from long-term survival. The standard chemotherapy combined with immunotherapy scheme recommended by the guidelines is TCb-AC combined with pabolizumab, but the complex chemotherapy scheme has the defects of long cycle and large adverse reactions, and the scheme of chemotherapy reduction has been explored.

This project plans to adopt an ambispective 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 triple negative breast cancer patients with clinical stage T2 and above and/or lymph node positive who received neoadjuvant therapy (TCb-AC combined with immunotherapy, or TCb combined with immunotherapy) admitted to the center from January 1, 2019 to November 31, 2024. Patients of the same type from December 1, 2024 to December 31, 2028 were prospectively included. The efficacy and safety of different treatment regimens were compared.

Investigators retrospectively recruited the triple negative breast cancer patients with clinical stage T2 and above and/or lymph node positive who received neoadjuvant therapy (TCb-AC combined with immunotherapy, TCb combined with immunotherapy, or TCb chemotherapy only) admitted to the center from January 1, 2019 to November 31, 2024. Patients of the same type from December 1, 2024 to December 31, 2028 were prospectively included. The efficacy and safety of different treatment regimens were compared.

Inclusion Criteria:

1. Patients with triple negative 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

Primary end point: pathology complete response

Inclusion Criteria:

• 1) Patients with triple negative 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

triple negative breast cancer patients who received neoadjuvant chemotherapy based on taxanes combined with carboplatin