• Patient is an adult female ≥18 and ≤75 years old at the time of informed consent.

• ECGO rating 0-3.

• Histologically or cytologically confirmed breast cancer.

• Cerebrospinal fluid cytology combined with central nervous system function and brain imaging demonstrated the diagnosis of breast cancer with meningeal metastases;

• Patients can be implanted or have been implanted with Ommaya reservoirs;

• Patient must have at least one measurable lesion (according to RECIST 1.1 criteria);

• Postmenopausal or pre/perimenopausal female patients are eligible for enrolment; pre or perimenopausal female patients must be willing to receive LHRHa during the study period.

• All patients were required to meet the following laboratory biochemical values prior to enrolment:

‣ Haematology: Hb ≥90 g/L, WBC ≥3.5×109/L, ANC ≥1.5×109/L, PLT ≥100×109/L;

⁃ Liver function: for those without liver metastases, AST, ALT, ALP ≤2.5 times the upper limit of normal values, and ≤1.25 x the upper limit of normal values for total bilirubin; for those with liver metastases, AST, ALT, ALP ≤ 5 times the upper limit of normal value, and total bilirubin ≤ 1.5 x upper limit of normal value.