MAMMI-BB PET for Monitoring Response to Neoadjuvant Therapy in Breast Cancer

This prospective, single-center, open-label, single-arm study will evaluate MAMMI-BB positron emission tomography (PET) for monitoring response to neoadjuvant therapy in patients with breast cancer and baseline axillary lymph node involvement. Serial PET examinations will measure changes in maximum standardized uptake value (SUVmax) in breast lesions and axillary lymph nodes. These changes will be compared with surgical pathology to assess their ability to predict pathologic complete response separately in the breast and axilla and to identify the most informative assessment time point. Associations between PET parameters and long-term outcomes, including progression-free survival and disease-free survival, will also be explored.

Inclusion Criteria: 1. Primary invasive breast carcinoma confirmed by core needle biopsy of the breast lesion. 2. Clinical stage cT1-4N0-3M0. 3. Age 18 to 70 years. 4. Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 2. 5. Hepatic, renal, and cardiac function adequate to tolerate chemotherapy and targeted therapy, as applicable. 6. Planned neoadjuvant chemotherapy with or without targeted therapy. 7. Provision of informed consent before study participation. Exclusion Criteria: 1. Pregnancy or breastfeeding. 2. Previous surgery or radiotherapy involving the ipsilateral axillary lymph nodes. 3. Diabetes mellitus or allergy to the radiotracer rendering the patient unsuitable for 18F-FDG PET/CT examination. 4. A history of, or concurrent, malignancy other than breast cancer, except non-melanoma skin cancer, carcinoma in situ of the cervix, or another malignancy considered cured with no evidence of recurrence for at least 5 years. Psychiatric illness or another condition affecting compliance with study requirements. 5. Serious disease or medical conditions, including:- Congestive heart failure, unstable angina, myocardial infarction within 6 months before enrollment, hypertension considered uncontrolled by the investigator, or high-risk uncontrolled arrhythmia. * Significant neurological or psychiatric disorders that may impair understanding or provision of informed consent. * Uncontrolled acute infection. 6. An allergic predisposition or known or suspected allergy to any study medication. 7. Any other condition that, in the investigator's judgment, makes the patient unsuitable for study participation.