A Study of Diarrhea and Intestinal Flora Changes Caused by Pyrotinib in Breast Cancer

Inclusion Criteria

• •1. Female breast cancer patients aged 18-75 years.
• •2. ECOG performance status of 0 to 1;
• •3. Known hormone receptor status;
• •4. HER2 positive breast cancer and previously reveived ≤2 anti-HER2 therapy;
• •5. Breast cancer patients are about to receive pyrotinib monotherapy or combined with Trastuzumab/Inetetamab and chemotherapy；
• •6. Patients with adequate organ function before enrollment (no blood transfusion, no white blood cell or platelet-elevating drugs used within 2 weeks before screening): 1) Blood routine:ANC≥1.5×10\^9/L; PLT≥90×10\^9/L; Hb≥90 g/L；2)Blood biochemistry: TBIL≤1.5×ULN;ALT and AST ≤1.5×ULN; alkaline phosphatase ≤ 2.5×ULN; BUN and Cr≤1.5×ULN；3) Cardiac color Doppler ultrasound:LVEF≥55%；4) 12-lead ECG: QTcF \< 470 msec;
• •7. Signed the informed consent form prior to patient entry, and have good compliance and are willing to cooperate with follow-up.