Comparative Effectiveness of Palbociclib Plus AI Versus Fulvestrant for HR+/HER2- ABC

Comparative Effectiveness of Palbociclib Plus Aromatase Inhibitor Versus Fulvestrant Alone as Initial Endocrine Therapy for HR+/HER2- Advanced Breast Cancer in Chinese Clinical Practice: a Real-world Study

A retrospective cohort study conducted at the Cancer Hospital Chinese Academy of Medical Sciences to compare the effectiveness of palbociclib plus AI therapy and fulvestrant monotherapy as initial endocrine therapy in the patients with HR+/HER2- advanced breast cancer.

This study is designed to be a retrospective cohort study conducted at the Cancer Hospital Chinese Academy of Medical Sciences. The target populations of this study are patients with HR+/HER2- advanced breast cancer who received the initial endocrine therapy of palbociclib plus AI or fulvestrant monotherapy from August 1, 2018 to December 31, 2020. It is expected to enroll 600 subjects in this study. The subjects' data such as demographics and other baseline characteristics, medications, prognosis, will be collected retrospectively, and statistical analysis of data will be conducted to compare the effectiveness outcome measures.

Inclusion Criteria:

1. Chinese women ≥18 years old;
2. Diagnosed with locally advanced (stage IIIb/IIIc) or metastatic (stage IV) breast cancer;
3. The molecular classification is pathologically confirmed as HR+/HER2-;
4. Palbociclib plus AI or fulvestrant monotherapy as initial endocrine therapy for advanced breast cancer for at least 1 cycle;
5. The follow-up time should be not less than 3 months after the start of palbociclib plus AI therapy or fulvestrant monotherapy.

Exclusion Criteria:

1. Subjects who have previously received chemotherapy, other CDK4/6 inhibitors or other endocrine monotherapy for advanced breast cancer.