Randomized phase II trial targeting early-stage breast cancer (stage II-III) applicable to preoperative chemotherapy (NAC), comparing standard treatment with multiple experimental treatments.

This randomized phase II trial targets early-stage breast cancer (stage II-III) with preoperative chemotherapy (NAC). It compares standard treatment with multiple experimental treatments using an adaptive design, allowing new treatments to be added during or after the trial. Patients are classified by subtype and randomized between standard and experimental treatments.

The trial is flexible, permitting single or combination new drug therapies and incorporating circulating tumor DNA (ctDNA) evaluation for precise efficacy and prognosis prediction.

Inclusion Criteria:

1. Histologically or cytologically confirmed invasive breast carcinoma
2. Stage II or III
3. ECOG performance status of 0 or 1
4. Age 18-80

Exclusion Criteria:

1. Continuous systemic administration (oral or intravenous) of steroid drugs or other immunosuppressants.
2. History or complication of interstitial lung disease or pulmonary fibrosis diagnosed by imaging or clinical findings.
3. Infection requiring systemic treatment.
4. Active double cancer (however, the following are not excluded: (1) Completely resected cancers: basal cell carcinoma, squamous cell carcinoma at clinical stage I, carcinoma in situ, mucosal carcinoma, superficial bladder carcinoma, (2) Gastrointestinal cancer that has been curatively resected by ESD or EMR, (3) Other cancers that have not recurred for more than 5 years).