The incidence of oral mucositis associated with TROP2-ADC therapy in patients with advanced breast cancer is notably high. Identifying effective preventive and therapeutic strategies is essential for enhancing patient quality of life and optimizing treatment outcomes. Oral cryotherapy has been demonstrated to be efficacious in mitigating oral mucositis induced by radiotherapy and chemotherapy. Consequently, this study seeks to investigate the potential preventive efficacy of oral cryotherapy on TROP2-ADC-induced oral mucositis in patients with advanced breast cancer

Inclusion Criteria:

1. Participants voluntarily enrolled in the study, signed the informed consent form, and demonstrated good compliance.

2. Age ≥ 18 years at the time of informed consent signing.

3. Patients with locally advanced or recurrent/metastatic breast cancer receiving TROP2-ADC treatment for the first time.

4. ECOG PS: 0-2 points;

5. The expected survival time was more than 3 months;

6. Adequate organ and bone marrow function, with no transfusions or treatments with recombinant human thrombopoietin or colony-stimulating factors within 1 week before the first dose, is defined as follows:

   1. Blood routine: Neutrophil count (NEUT#) ≥ 1.5×109/L; Platelet (PLT) ≥ 75×109/L; Hemoglobin ≥ 90g/L
   2. Liver function: AST and ALT ≤ 3 × ULN; for patients with liver metastasis, AST and ALT ≤ 5 × ULN.
   3. Renal function: Creatinine ≤ 1.5 × ULN or Ccr ≥ 60 ml/min (Cockcroft-Gault formula provided).
   4. Cardiac function: LVEF ≥ 50% by ECHO or MUGA scan.

7. Patients with a negative pregnancy test and reproductive potential must agree to use effective non-hormonal contraception during treatment and for at least 3 months after the last dose of the investigational drug.

8. Voluntary participants who sign informed consent, demonstrate good compliance, and agree to follow-up.

Exclusion Criteria:

1. Prior TROP2-targeted treatment was administered.
2. Patients with active oral mucositis or oral ulcers were excluded.
3. Patients with serious concomitant diseases, as judged by researchers, that threaten safety or impede study completion, including uncontrolled hypertension, severe diabetes, and active infections, were excluded.
4. Other conditions where the investigator determines the patient is unsuitable for study participation.