We are doing this study to determine if long-term treatment with camizestrant after surgery is a safe and effective option for treating patients with early-stage ER+/HER2- breast cancer. We want to compare the outcomes of using camizestrant to current standard of care treatments (endocrine therapy).

Early Stage ER+/HER2- Breast Cancer

Adults ages 18+ who:

• Are diagnosed with intermediate or high-risk early stage ER+/HER2- breast cancer
• Have had surgery to remove breast cancer tissue
• Have been taking endocrine therapy for 2-5 years after surgery

For more information about who can join this study, please contact the study team at caroline.morales@duke.edu.

If you choose to join this study, you will get a random assignment (like a coin flip) to 1 of 2 groups:

• One group will take physician's choice endocrine therapy daily
• The other group will take camizestrant daily

Participants in both groups will:

• Answer questionnaires
• Have blood draws
• Have imaging scans
• Have eye exams
• Have heart scans (EKGs)
• Give us permission to use your stored tissue samples

After study treatment, you will continue to return to our clinic for follow-up visits to see how you are doing.