NCT06127979 · Memorial Sloan Kettering Cancer Center
A Study of Changes in Ki67 Expression in People With Breast Cancer Receiving Endocrine Therapy Before Surgery
What this study is about
The researchers are doing this study to look at changes in Ki67 expression after at least 2 weeks of endocrine therapy in people with ER+/HER2- breast cancer undergoing cancer removal surgery. Participants will receive the endocrine therapy before their surgery.
View original scientific description
The researchers are doing this study to look at changes in Ki67 expression after at least 2 weeks of endocrine therapy in people with ER+/HER2- breast cancer undergoing cancer removal surgery. Participants will receive the endocrine therapy before their surgery. The researchers will look at how changes in Ki67 expression compare between participants who are carriers of the BRCA2 mutation and participants who are noncarriers of the BRCA2 mutation.
Interventions
PROCEDURE
core needle biopsy
Pre-Endocrine Therapy core needle biopsy. The pre-treatment research biopsy will require a biopsy marker clip to document that the cancer lesion was biopsied
OTHER
blood draw
blood draw
Primary outcome measures
assess the change in Ki67
Time frame: baseline to at least 2 weeks of endocrine therapy
The change in Ki67 expression on immunohistochemical staining from baseline to at least 2 weeks of ET will be assessed.
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- Postmenopausal women aged ≥18 years with biopsy-proven stage I-III invasive breast cancer that is ER+/HER2-
- Scheduled to undergo upfront surgery
- Eligible for genetic testing in accordance with National Comprehensive Cancer Network guidelines(BRCA2 arm only)
Exclusion criteria
- History of breast cancer
- Receipt of ET for risk reduction in the previous 3 months
- Stage IV disease at presentation
- Scheduled to undergo neoadjuvant systemic chemotherapy
Where
- New York, New York
Related conditions & keywords
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Jun 2, 2026 · Source of record for eligibility and locations