Stage III Breast CancerPhase 2NCT07314073
[18F]FES PET/CT for the Detection of Distant Metastasis in Low-grade ER-positive Stage III Breast Cancer
A Phase 2 study testing Fluoroestradiol (18F) in people with Stage III Breast Cancer, run by Asan Medical Center at 1 site in South Korea.
Trial summary
This study aims to evaluate the detection rate of distant metastases using [18F]FES PET/CT in patients with low-grade, ER-positive stage III breast cancer. Read more about this study
- Who is it for?
- Ages 19 years and older
- Conditions the study is for
- Stage III Breast Cancer
- What is being tested?
- Fluoroestradiol (18F)
- Type of treatment
- Injection or infusion
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 85 participants
- Where
- 1 siteSouth Korea
- Study dates
- 24 Dec 2025to 31 Dec 2029
- Phase
- Phase 2
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 19 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Male or female patients aged ≥19 years, regardless of race/ethnicity
- Patients newly diagnosed with invasive breast cancer within 90 days prior to screening, with documented histopathological confirmation.
- Patients diagnosed with histologically confirmed estrogen receptor-positive, histologic grade 1 or 2 primary breast cancer
- Patients with clinical stage IIIA-IIIC disease according to the 8th edition of the American Joint Committee on Cancer (AJCC) TNM staging system
- Patients who have undergone, or are scheduled to undergo chest computed tomography (CT), abdominal CT, and bone scintigraphy within 90 days prior to screening before the 18F-FES PET/CT scan
- Patients with an Eastern Cooperative Oncology Group (ECOG) performance status (PS) score of ≤2
Who cannot join
- The subject or the subject's legally authorized representative has not signed the informed consent form
- Subjects who are currently receiving systemic therapy for breast cancer (e.g., neoadjuvant chemotherapy, hormonal therapy)
- Subjects with a history of another invasive malignancy within the past 2 years (except for non-melanoma skin cancer)
- Subjects diagnosed with distant metastases on chest CT, abdominal CT, or bone scintigraphy performed within 90 days prior to screening or before the 18F-FES PET/CT scan
- Subjects for whom neither biopsy nor ≥6 months of follow-up imaging has been performed for lesions suspicious for distant metastases
- Pregnant or breastfeeding women. The following cases are considered not at risk of pregnancy: (1) physiologically postmenopausal (no menses for ≥2 years), (2) surgically sterile (history of bilateral oophorectomy or hysterectomy), (3) women of childbearing potential with a documented negative serum or urine pregnancy test within 24 hours prior to 18F-FES administration, and who agree to use effective contraception during the trial.
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- Subjects with serious and/or uncontrolled and/or unstable medical conditions (e.g., congestive heart failure, acute myocardial infarction, severe pulmonary disease, chronic kidney disease, or chronic liver disease)
- Subjects who are relatives or students of the investigator, or otherwise in a dependent relationship with the investigator
- Subjects who, in the judgment of the investigator, are unable to provide complete data for the clinical trial due to personal circumstances or other reasons
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
South Korea1 site, 1 recruiting
- Recruiting
Asan Medical Center
Seoul
Sangwon Han, +82-2-3010-0657, hswon87@amc.seoul.kr
About this study
Official title: A Phase 2, Open-label, Non-randomized, Single Center Study Evaluating 18F-Fluoroestradiol Positron Emission Tomography/Computed Tomography for the Detection of Distant Metastases in Low-grade, Estrogen Receptor-positive Stage III Breast Cancer
This study aims to evaluate the detection rate of distant metastases using [18F]FES PET/CT in patients with low-grade, ER-positive stage III breast cancer.
Read the detailed description
Breast cancer is highly prevalent, and approximately 75% of cases are estrogen receptor (ER)-positive. Stage III breast cancer carries a significant risk of distant metastasis; therefore, NCCN and ESMO guidelines recommend systemic staging with CT, bone scan, or 18F-FDG PET/CT. However, 18F-FDG PET/CT demonstrates limited sensitivity in low-grade ER-positive tumors and invasive lobular carcinoma (ILC), and can yield false positives due to inflammatory reaction or reactive hyperplasia. Thus, more accurate imaging modalities are needed in this subgroup.
18F-fluoroestradiol (18F-FES) PET/CT visualizes ER expression and has shown high concordance with histopathology. A phase III study demonstrated 77% sensitivity and 100% specificity for metastatic disease. Emerging evidence suggests that 18F-FES PET/CT may detect distant or regional lymph node metastases more accurately than standard imaging, particularly in ILC and low-grade tumors, and can influence management decisions such as surgery and radiotherapy planning.
Accurate identification of regional nodal involvement (axillary, supraclavicular, internal mammary nodes) is essential for determining the extent of axillary surgery after neoadjuvant chemotherapy and for tailoring regional nodal irradiation. Prior studies show that metabolic imaging can alter radiotherapy fields in up to 40% of patients.
The primary objective is to determine the patient-based detection rate of qualitative 18F-FES PET/CT for distant metastases. Secondary objectives include evaluating its patient-based sensitivity and specificity for distant metastases; determining the detection rate, sensitivity, and specificity for cN3 lymph node metastases (infraclavicular, supraclavicular, and internal mammary nodes); assessing the rate of management change attributable to 18F-FES PET/CT; and comparing 18F-FES PET/CT with 18F-FDG PET/CT for detection rate, diagnostic accuracy, and management impact. Exploratory analyses will examine the correlation between qualitative and quantitative 18F-FES PET/CT findings and pathological response to neoadjuvant chemotherapy.
- Conditions
- Stage III Breast Cancer
- Being tested
- Fluoroestradiol (18F)
- Keywords
- breast cancer, estrogen receptor, [18F]FES PET/CT, distant metastasis
- Medical subject headings
- Breast Neoplasms
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Fluoroestradiol (18F)Diagnostic test
Images for 90 minutes after F-18 FES injection
| Study group | Role | What they receive |
|---|---|---|
| [18F]FES PET/CT | Experimental | Not described Receives: Diagnostic Test: Fluoroestradiol (18F) |
What is being measured
The primary outcome is the main question the study is designed to answer.
Patient based detection rate of qualitative [18F]FES PET/CT evaluation for distant metastases
Measured: Baseline (index [18F]FES PET/CT image interpretation performed within 1 week after PET/CT acquisition, prior to initiation of definitive treatment)
Secondary outcomes (6)
Patient-based sensitivity and specificity of qualitative [18F]FES PET/CT evaluation for distant metastases
Measured: From baseline [18F]FES PET/CT to confirmation of reference standard, assessed up to 6 months (histopathologic confirmation or clinical and imaging follow-up ≥6 months, through multidisciplinary consensus review)
Patient-based detection rate of qualitative [18F]FES PET/CT evaluation for cN3 lymph node metastases
Measured: Baseline (index [18F]FES PET/CT image interpretation performed within 1 week after PET/CT acquisition, prior to initiation of definitive treatment)
Patient-based sensitivity and specificity of qualitative [18F]FES PET/CT evaluation for cN3 lymph node metastases
Measured: From baseline [18F]FES PET/CT to confirmation of reference standard, assessed up to 6 months (histopathologic confirmation or clinical and imaging follow-up ≥6 months, through multidisciplinary consensus review)
Patient-based change rate in clinical management based on qualitative 18F-FES PET/CT evaluation
Measured: From baseline clinical management plan (pre-[18F]FES PET/CT) to final treatment decision after [18F]FES PET/CT, assessed within 4 weeks after PET/CT
Comparative patient-based evaluation of qualitative [18F]FES PET/CT and [18F]FDG PET/CT for detection rate of distant and cN3 lymph node metastases, and rate of change in clinical management
Measured: Baseline (paired [18F]FES PET/CT and [18F]FDG PET/CT image interpretation performed within 1 week after each PET/CT acquisition)
Comparative patient-based evaluation of qualitative [18F]FES PET/CT and [18F]FDG PET/CT for sensitivity, specificity of distant and cN3 lymph node metastases, and rate of change in clinical management
Measured: From baseline PET/CT imaging to confirmation of reference standard, assessed up to 6 months (histopathologic confirmation or clinical and imaging follow-up ≥6 months)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted2 Jan 2026
- Study start24 Dec 2025
- Primary completion31 Dec 2028 (estimated)
- Study completion31 Dec 2029 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Stage III Breast CancerStudies of the same condition, open and under way.
- More trials run by Asan Medical CenterThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 2
- Primary purpose
- Diagnosis
- Allocation
- Not applicable
- Intervention model
- Single group
- Model description
- A phase 2, open-label, non-randomized, single center study
- Masking
- None (open label)
- Enrolment
- 85 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Asan Medical Center
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Hyehyun Jeong, Asan Medical Center
- Investigators
- Hyehyun Jeong, Principal investigator, Asan Medical Center
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07314073
- Sponsor's protocol ID
- FES LABC
- Status last verified
- Dec 2025
- First submitted
- 3 Dec 2025
- Last updated
- 2 Jan 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 2 Jan 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Phase 2, Open-label, Non-randomized, Single Center Study Evaluating 18F-Fluoroestradiol Positron Emission Tomography/Computed Tomography for the Detection of Distant Metastases in Low-grade, Estrogen Receptor-positive Stage III Breast Cancer
- ClinicalTrials.gov ID
- NCT07314073
- Acronym / sponsor ID
- FES LABC
- Conditions
- Stage III Breast Cancer
- Keywords
- breast cancer, estrogen receptor, [18F]FES PET/CT, distant metastasis
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 85 participants (estimated)
- Lead sponsor
- Asan Medical CenterUniversity, hospital or other
- Study start
- 24 Dec 2025 (actual)
- Primary completion
- 31 Dec 2028 (estimated)
- Study completion
- 31 Dec 2029 (estimated)
- First posted
- 2 Jan 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This study aims to evaluate the detection rate of distant metastases using [18F]FES PET/CT in patients with low-grade, ER-positive stage III breast cancer.
Detailed description
Breast cancer is highly prevalent, and approximately 75% of cases are estrogen receptor (ER)-positive. Stage III breast cancer carries a significant risk of distant metastasis; therefore, NCCN and ESMO guidelines recommend systemic staging with CT, bone scan, or 18F-FDG PET/CT. However, 18F-FDG PET/CT demonstrates limited sensitivity in low-grade ER-positive tumors and invasive lobular carcinoma (ILC), and can yield false positives due to inflammatory reaction or reactive hyperplasia. Thus, more accurate imaging modalities are needed in this subgroup.
18F-fluoroestradiol (18F-FES) PET/CT visualizes ER expression and has shown high concordance with histopathology. A phase III study demonstrated 77% sensitivity and 100% specificity for metastatic disease. Emerging evidence suggests that 18F-FES PET/CT may detect distant or regional lymph node metastases more accurately than standard imaging, particularly in ILC and low-grade tumors, and can influence management decisions such as surgery and radiotherapy planning.
Accurate identification of regional nodal involvement (axillary, supraclavicular, internal mammary nodes) is essential for determining the extent of axillary surgery after neoadjuvant chemotherapy and for tailoring regional nodal irradiation. Prior studies show that metabolic imaging can alter radiotherapy fields in up to 40% of patients.
The primary objective is to determine the patient-based detection rate of qualitative 18F-FES PET/CT for distant metastases. Secondary objectives include evaluating its patient-based sensitivity and specificity for distant metastases; determining the detection rate, sensitivity, and specificity for cN3 lymph node metastases (infraclavicular, supraclavicular, and internal mammary nodes); assessing the rate of management change attributable to 18F-FES PET/CT; and comparing 18F-FES PET/CT with 18F-FDG PET/CT for detection rate, diagnostic accuracy, and management impact. Exploratory analyses will examine the correlation between qualitative and quantitative 18F-FES PET/CT findings and pathological response to neoadjuvant chemotherapy.
Study design
- Primary purpose
- Diagnosis
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
- Model description
- A phase 2, open-label, non-randomized, single center study
| Arm | Type | Receives |
|---|---|---|
| [18F]FES PET/CT | Experimental | Diagnostic Test: Fluoroestradiol (18F) |
Who may qualify
- Ages
- 19 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (6 listed)
- Male or female patients aged ≥19 years, regardless of race/ethnicity
- Patients newly diagnosed with invasive breast cancer within 90 days prior to screening, with documented histopathological confirmation.
- Patients diagnosed with histologically confirmed estrogen receptor-positive, histologic grade 1 or 2 primary breast cancer
- Patients with clinical stage IIIA-IIIC disease according to the 8th edition of the American Joint Committee on Cancer (AJCC) TNM staging system
- Patients who have undergone, or are scheduled to undergo chest computed tomography (CT), abdominal CT, and bone scintigraphy within 90 days prior to screening before the 18F-FES PET/CT scan
Key exclusion criteria (9 listed)
- The subject or the subject's legally authorized representative has not signed the informed consent form
- Subjects who are currently receiving systemic therapy for breast cancer (e.g., neoadjuvant chemotherapy, hormonal therapy)
- Subjects with a history of another invasive malignancy within the past 2 years (except for non-melanoma skin cancer)
- Subjects diagnosed with distant metastases on chest CT, abdominal CT, or bone scintigraphy performed within 90 days prior to screening or before the 18F-FES PET/CT scan
- Subjects for whom neither biopsy nor ≥6 months of follow-up imaging has been performed for lesions suspicious for distant metastases
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Fluoroestradiol (18F)Images for 90 minutes after F-18 FES injection | Diagnostic test | [18F]FES PET/CT |
Primary outcome
Patient based detection rate of qualitative [18F]FES PET/CT evaluation for distant metastases
Time frame: Baseline (index [18F]FES PET/CT image interpretation performed within 1 week after PET/CT acquisition, prior to initiation of definitive treatment)
6 secondary outcomes
Patient-based sensitivity and specificity of qualitative [18F]FES PET/CT evaluation for distant metastases
Time frame: From baseline [18F]FES PET/CT to confirmation of reference standard, assessed up to 6 months (histopathologic confirmation or clinical and imaging follow-up ≥6 months, through multidisciplinary consensus review)
Patient-based detection rate of qualitative [18F]FES PET/CT evaluation for cN3 lymph node metastases
Time frame: Baseline (index [18F]FES PET/CT image interpretation performed within 1 week after PET/CT acquisition, prior to initiation of definitive treatment)
Patient-based sensitivity and specificity of qualitative [18F]FES PET/CT evaluation for cN3 lymph node metastases
Time frame: From baseline [18F]FES PET/CT to confirmation of reference standard, assessed up to 6 months (histopathologic confirmation or clinical and imaging follow-up ≥6 months, through multidisciplinary consensus review)
Patient-based change rate in clinical management based on qualitative 18F-FES PET/CT evaluation
Time frame: From baseline clinical management plan (pre-[18F]FES PET/CT) to final treatment decision after [18F]FES PET/CT, assessed within 4 weeks after PET/CT
Comparative patient-based evaluation of qualitative [18F]FES PET/CT and [18F]FDG PET/CT for detection rate of distant and cN3 lymph node metastases, and rate of change in clinical management
Time frame: Baseline (paired [18F]FES PET/CT and [18F]FDG PET/CT image interpretation performed within 1 week after each PET/CT acquisition)
Comparative patient-based evaluation of qualitative [18F]FES PET/CT and [18F]FDG PET/CT for sensitivity, specificity of distant and cN3 lymph node metastases, and rate of change in clinical management
Time frame: From baseline PET/CT imaging to confirmation of reference standard, assessed up to 6 months (histopathologic confirmation or clinical and imaging follow-up ≥6 months)
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 2 Jan 2026.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Hyehyun Jeong principal investigator
Asan Medical Center
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing Fluoroestradiol (18F) in people with Stage III Breast Cancer, run by Asan Medical Center at 1 site in South Korea.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 6 inclusion and 9 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 2 Jan 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in South Korea. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Sangwon Han (+82-2-3010-0657, hswon87@amc.seoul.kr), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Patient based detection rate of qualitative [18F]FES PET/CT evaluation for distant metastases (time frame: Baseline (index [18F]FES PET/CT image interpretation performed within 1 week after PET/CT acquisition, prior to initiation of definitive treatment)). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 2 Jan 2026.