This study is a prospective, exploratory clinical study design, and plans to enroll 33 patients with HR+HER2 low expression breast cancer who received pyrotinib combined with darcili and standard endocrine neoadjuvant therapy to evaluate the efficacy of this regimen in HR+HER2 low expression breast cancer. Imaging evaluation was performed according to RECIST 1.1 criteria, and tumor imaging evaluation was performed by the participating center. The pathological evaluation after surgery of neoadjuvant patients was the pCR assessed by the pathologist of the participating center.
Female patients aged ≥18 years and ≤75 years old, who have just been treated for breast cancer;
Pathological examination confirmed that HR was positive (ER≥10%) and HER2 was low (immunohistochemical staining ICH++ and FISH negative);
Patients with invasive breast cancer confirmed by pathological examination (T≥3 or N≥1) who are eligible for neoadjuvant therapy;
ECOG score 0~1 points;
Those who have a known history of allergy to the drug components of this regimen;
Previous anti-tumor therapy or radiotherapy for any malignant tumor (except for cured cervical carcinoma in situ and basal cell carcinoma);
Underwent major surgical procedures unrelated to breast cancer within 4 weeks, or patients have not fully recovered from such surgical procedures;
Patients with stage IV (metastatic) breast cancer;