Serial FES PET/CT to Measure Hormone Expression in Patients Undergoing Endocrine Targeted Therapy
June 15, 2026 updated by: Delphine Chen, University of Washington
Serial [F-18] Fluoroestradiol (FES) PET Imaging to Evaluate Endocrine-targeted Therapy
This clinical trial studies use of F-18 16 alpha-fluoroestradiol ([F-18] FES) positron emission tomography (PET)/computed tomography (CT) in measuring tumor hormone receptor expression in patients undergoing endocrine-targeted therapy for newly diagnosed breast cancer or breast cancer that has come back or spread to other places in the body.
Comparing results of diagnostic procedures done before, during, and after hormone therapy may help measure a patient's response to treatment.
Study Overview
Status
Active, not recruiting
Conditions
Detailed Description
OUTLINE:
Patients undergo F-18 FES PET/CT scan at baseline. Patients also undergo F-18 FES PET/CT and FDG PET/CT between 1-12 weeks after starting therapy, and then 1-12 weeks after the second FES PET/CT scan. Repeat FDG PET may be omitted in patients on selective estrogen receptor degrader.
After completion of study, patients are followed up for up to 20 years.
Study Type
Interventional
Enrollment (Actual)
2
Phase
- Phase 2
Contacts and Locations
This section provides the contact details for those conducting the study, and information on where this study is being conducted.
Study Locations
-
-
Washington
-
Seattle, Washington, United States, 98109
- Fred Hutch/University of Washington Cancer Consortium
-
-
Participation Criteria
Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.
Eligibility Criteria
Ages Eligible for Study
18 years and older (Adult, Older Adult)
Accepts Healthy Volunteers
No
Description
Inclusion Criteria:
- Adult, non-pregnant patients with biopsy-proven or clinically obvious primary, recurrent or metastatic breast cancer
- Breast cancer from ER+ primary that is seen on other imaging tests. Tumor ER expression must have been confirmed by immunohistocytochemistry of primary tumor or recurrent disease.
- At least one site of disease 1.5 cm or greater is needed to meet the spatial resolution limits of PET imaging.
- Patients must have been off tamoxifen or other estrogen receptor blocking agents for at least 6 weeks and off chemotherapy for 3 weeks for the initial baseline FES.
- Patients must be selected for an endocrine targeted therapy regimen for treatment of their breast cancer by the referring oncologist. Selected treatments may be part of experimental treatment protocols for which the patient would be separately consented.
- Patients must be willing to undergo serial imaging procedures.
- Patients must agree to allow access to clinical records regarding response to treatment and long term follow up.
- Ability to understand and the willingness to sign a written informed consent document.
Exclusion Criteria:
- An inability to lie still for the tests
- Individuals weighing more than 300 lb. (this is the weight limit of the scanner table)
- Pregnant or lactating. Women of childbearing potential with either a positive or no pregnancy test at baseline are excluded.
- Any other life-threatening illness (e.g. serious, uncontrolled concurrent infection or clinically significant cardiac disease - congestive heart failure, symptomatic coronary artery disease, cardiac arrhythmia not well controlled with medication).
- Use of tamoxifen, faslodex, DES or any other ER blocking agent < 6 weeks or chemotherapy < 3 weeks prior to imaging scan.
- Uncontrolled diabetes mellitus (fasting glucose > 200 mg/dL)
- Adult patients who require monitored anesthesia for PET scanning.
Study Plan
This section provides details of the study plan, including how the study is designed and what the study is measuring.
How is the study designed?
Design Details
- Primary Purpose: Diagnostic
- Allocation: N/A
- Interventional Model: Single Group Assignment
- Masking: None (Open Label)
Arms and Interventions
Participant Group / Arm |
Intervention / Treatment |
|---|---|
|
Experimental: Diagnostic (F-18 FES PET/CT)
Patients undergo F-18 FES PET/CT scan at baseline.
Patients also undergo F-18 FES PET/CT and FDG PET/CT between 1-12 weeks after starting therapy, and then 1-12 weeks after the second FES PET/CT scan.
Repeat FDG PET may be omitted in patients on selective estrogen receptor degrader.
|
Correlative studies
Undergo FDG PET/CT
Other Names:
Undergo FDG PET/CT
Other Names:
Undergo F-18 FES PET/CT
Other Names:
Undergo F-18 FES PET/CT
Other Names:
Undergo FDG PET/CT
Other Names:
Undergo F-18 FES PET/CT
Other Names:
|
What is the study measuring?
Primary Outcome Measures
Outcome Measure |
Measure Description |
Time Frame |
|---|---|---|
|
Change in F-18 16 Alpha-fluoroestradiol (FES) Standardized Uptake Value (SUV) - Avg SULmax
Time Frame: From time of first F-18 FES-PET/CT scan to time of second F-18 FES-PET/CT scan (approximately 1-12 weeks)
|
FES uptake will be quantified using lean body mass adjusted SUV (SUL).
Percentage change in FES average SULmax between baseline and a second FES scan will be calculated for up to 3 lesions per patient.
|
From time of first F-18 FES-PET/CT scan to time of second F-18 FES-PET/CT scan (approximately 1-12 weeks)
|
|
F-18 16 Alpha-fluoroestradiol (FES) Uptake
Time Frame: From time of first F-18 FES-PET/CT scan to time of second F-18 FES-PET/CT scan (approximately 1-12 weeks)
|
Quantitative measures of FES uptake for each disease site will be determined by drawing regions-of-interest on lesions to determine maximal FES uptake (SUVmax) per lesion.
Up to 10 sites seen on the static torso survey will be quantified.
|
From time of first F-18 FES-PET/CT scan to time of second F-18 FES-PET/CT scan (approximately 1-12 weeks)
|
|
Proportion of Patients With a Threshold of Percentage Change, or That Surpass a Targeted Follow-up F-18 16 Alpha-fluoroestradiol (FES) Standardized Uptake Value (SUV)
Time Frame: From time of first F-18 FES-PET/CT scan to time of second F-18 FES-PET/CT scan (approximately 1-12 weeks)
|
The number of patients showing a 20% increase in FES uptake (SULmean or SUVmax) compared to baseline from the first to second scan using a 90% Wilson score binomial confidence interval.
|
From time of first F-18 FES-PET/CT scan to time of second F-18 FES-PET/CT scan (approximately 1-12 weeks)
|
Secondary Outcome Measures
Outcome Measure |
Measure Description |
Time Frame |
|---|---|---|
|
Time to Disease Progression
Time Frame: From start of therapy up to 20 years
|
Time to disease progression will be measured as the time from the start of endocrine therapy to the time the patient is first recorded as having disease progression.
|
From start of therapy up to 20 years
|
Collaborators and Investigators
This is where you will find people and organizations involved with this study.
Sponsor
Investigators
- Principal Investigator: Hannah Linden, Fred Hutch/University of Washington Cancer Consortium
Study record dates
These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.
Study Major Dates
Study Start (Actual)
July 10, 2021
Primary Completion (Actual)
October 1, 2021
Study Completion (Estimated)
April 30, 2041
Study Registration Dates
First Submitted
December 30, 2020
First Submitted That Met QC Criteria
December 30, 2020
First Posted (Actual)
December 31, 2020
Study Record Updates
Last Update Posted (Actual)
July 1, 2026
Last Update Submitted That Met QC Criteria
June 15, 2026
Last Verified
April 1, 2026
More Information
Terms related to this study
Additional Relevant MeSH Terms
- Neoplasms by Site
- Neoplasms
- Skin Diseases
- Breast Diseases
- Skin and Connective Tissue Diseases
- Breast Neoplasms
- Investigative Techniques
- Carbohydrates
- Physical Phenomena
- Chemistry Techniques, Analytical
- Spectrum Analysis
- Electromagnetic Phenomena
- Magnetic Phenomena
- Deoxyglucose
- Deoxy Sugars
- Electromagnetic Radiation
- Radiation
- Radiation, Ionizing
- Fluorodeoxyglucose F18
- Magnetic Resonance Spectroscopy
- X-Rays
- 16-fluoroestradiol
Other Study ID Numbers
- RG1007834
- 10465 (Other Identifier: Fred Hutch/University of Washington Cancer Consortium)
Plan for Individual participant data (IPD)
Plan to Share Individual Participant Data (IPD)?
NO
Drug and device information, study documents
Studies a U.S. FDA-regulated drug product
Yes
Studies a U.S. FDA-regulated device product
No
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