This study aimed to evaluate the feasibility and safety, and to observe early efficacy signals of the focused ultrasound mediated drug delivery system combined with SonoVue® in patients with HER2-positive breast cancer receiving neoadjuvant therapy by comparing its pathological complete response (pCR) rate with a matched historical cohort of HER2-positive breast cancer patients treated at our center.

Inclusion Criteria:

1. Female patients aged 18-70 years.
2. Histologically confirmed HER2 positive breast cancer, with indication for neoadjuvant chemotherapy, and scheduled to receive the T(P)CbHP neoadjuvant regimen.
3. TNM stage T2N0-2M0.
4. Adequate bone marrow reserve (ANC >1.5×10⁹/L, platelets >100×10⁹/L).
5. Normal liver function (ALAT, ASAT, and bilirubin <2.5× upper limit of normal).
6. Adequate renal function (creatinine clearance >50 mL/min).
7. Left ventricular ejection fraction (LVEF) ≥50% measured by echocardiography or MUGA.
8. No psychological, family, social, or geographical conditions that would compromise compliance with the study protocol and follow-up schedule.
9. No medical conditions that would place the subject at undue risk.
10. Written informed consent signed by the subject.

Exclusion Criteria:

1. Prior history of radiotherapy or chemotherapy.
2. Pregnant or lactating patients.
3. Presence of distant metastasis.
4. Bilateral invasive breast cancer.
5. Concurrent administration of other anticancer therapies or another investigational agent.
6. inadequate physical tolerance, including significant cardiovascular, hepatic, or renal dysfunction, massive ascites, intestinal obstruction, severe infection, high fever, as well as water-electrolyte and acid-base imbalance.
7. Patients with known hyper sensitivity to SonoVue®.