This prospective observational study will enroll up to 200 patients with advanced hormone receptor-positive breast cancer whose cancer has progressed after their first treatment. The goal is to evaluate whether a blood-based biomarker, called the PERDI score, can predict how well patients respond to a second line hormone therapy.
Participants will provide a blood sample before starting treatment, with optional additional samples collected during treatment or at disease progression. Researchers will compare the blood test results with clinical outcomes, including how long the cancer remains under control, to determine whether the PERDI score can help identify patients who are most likely to benefit from treatment.
The study will be conducted across multiple sites within a single institution and will run for approximately 18 months, including a 12-month enrollment period and 6 months of follow-up. Findings from this study may help support more personalized treatment decisions and improve outcomes for patients with advanced breast cancer.
