Estrogen Receptor Positive Breast CancerPhase 2PRESTONCT02238808
A Study to See Whether Estrogen Can Slow the Growth of Some ER Positive Breast Cancers
A Phase 2 study testing Estradiol in people with Estrogen Receptor Positive Breast Cancer, run by AHS Cancer Control Alberta at 1 site in Canada.
Trial summary
Some breast cancers have estrogen receptors (ER+). The investigators know that some ER+ tumours can be cured by hormone therapy alone while other ER+ breast cancers cannot. Currently, there is no perfect way to tell these groups apart nor do the investigators know why some respond when others do not. Read more about this study
- Who is it for?
- Ages 55 years and older, women only
- Conditions the study is for
- Estrogen Receptor Positive Breast Cancer
- What is being tested?
- Estradiol
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 19 participants
- Where
- 1 siteCanada
- Study dates
- Aug 2015to Jun 2028
- 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 55 years and older
- Women only
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Female gender
- Estrogen receptor positive (ER+) breast cancer
- HER2 negative breast cancer
- Post-menopausal by greater than 5 years
- No previous hormonal replacement therapy
- Low to intermediate histologic grade
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- ECOG Performance status of 0 of 1
- Adequate hematological, renal and hepatic function is required
- Ability to take oral medication
- Patient must have adequate tissue for diagnosis, biomarkers and Ki67 assays
Who cannot join
- Pre-menopausal women
- Locally advanced or metastatic breast cancer
- Current, previous or planning for pre-operative treatment with chemotherapy, hormone therapy including corticosteroids, radiation therapy for malignancy or other condition
- Known hypersensitivity or intolerance to estradiol
- Ischemic changes on baseline electrocardiogram
- Symptomatic but untreated cholelithiasis
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- History of deep vein thrombosis, pulmonary embolism, stroke, acute myocardial infarction, congestive cardiac failure, untreated hypertension or known inherited hypercoagulable disorder
- Undiagnosed abnormal vaginal bleeding or prior history of endometrial cancer
- Untreated metabolic disturbances (glucose > 15.0 mmol/L and triglycerides > 400 mg/dL)
- Current treatment with drugs known to be moderate or strong inhibitors of inducers of isoenzyme CYP3A4
- The time between study enrolment and definitive breast surgery is not sufficient for administration of at least 7 days of estradiol
Trial locations and contacts
1 site in 1 country.
About this study
Official title: PRe-operative ESTradiOl Window of Opportunity Study in Post-Menopausal Women With Newly Diagnosed ER Positive Breast Cancer
Some breast cancers have estrogen receptors (ER+). The investigators know that some ER+ tumours can be cured by hormone therapy alone while other ER+ breast cancers cannot. Currently, there is no perfect way to tell these groups apart nor do the investigators know why some respond when others do not.
Research findings suggest that the two types of ER+ breast cancers differ in their response to estrogen with estrogen being toxic to one type and not the other. For those tumours that find estrogen toxic, this may explain why tumours only start to grow when estrogen levels decrease after menopause.
The purpose of this study is to see whether a two-week treatment of estrogen equal to pre-menopausal estrogen levels will decrease the rate at which patients' ER+ tumours grow. This will be done by comparing the growth rate in the tissue removed during standard of care surgery after patients have been treated with 7-14 days of estrogen prior to that surgery.
Read the detailed description
Breast cancer is a heterogeneous disease that includes two ER+ genetic subtypes (luminal A and luminal B) that differ in their response to treatment.
Results from the Women's Health Initiative Trial showed that estrogen treated hysterectomized women with no prior history of breast cancer had a significant and persistent decrease in breast cancer incidence when compared to placebo treated participants. This implies that some ER+ breast cancers are in fact growth inhibited by estrogens and are not growth promoted.
The hypothesis of this study is that some ER+ breast cancers (luminal A) are actually sensitive (growth inhibited) by estrogen.
Objectives:
- To assess changes in breast cancer proliferation after a 7-14 day trial of estradiol in newly diagnosed estrogen receptor positive post-menopausal breast cancer patients prior to surgery.
- Exploratory analysis of biologic correlates with comparison to available genotyping tests.
This is an open-label single group assignment pilot study for safety/efficacy and exploratory biologic correlates
- Conditions
- Estrogen Receptor Positive Breast Cancer
- Being tested
- Estradiol
- Keywords
- ER+ breast cancer, Luminal A, Estradiol
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
EstradiolDrug
Also called estrogen
Eligible participants will take 2 mg Estradiol 3 times daily for 7-14 days pre-surgery.
| Study group | Role | What they receive |
|---|---|---|
| Estradiol treatment | Experimental | Estradiol 6 mg daily for 7-14 days Receives: Drug: Estradiol |
What is being measured
The primary outcome is the main question the study is designed to answer.
To assess changes in breast cancer proliferation after a 7-14 day trial of estradiol in newly diagnosed estrogen receptor positive post-menopausal breast cancer patients prior to surgery.
Measured: end of 7-14 day treatment with estradiol
Secondary outcomes (2)
Exploratory analysis of biologic correlates with comparison to available genotyping tests
Measured: end of 7-14 day treatment with estradiol
Analysis of recurrence/survival data based on initial Ki67 response to 7-14 day trial of estradiol.
Measured: 10 years
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted12 Sep 2014 (estimated)
- Study startAug 2015
- Primary completion30 Jul 2018
- Study completionJun 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Estrogen Receptor Positive Breast CancerStudies of the same condition, open and under way.
- 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
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 19 participants (actual)
Sponsor and investigators
- Lead sponsor
- AHS Cancer Control Alberta
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Judith Hugh, MD, Principal investigator, University of Alberta
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT02238808
- Sponsor's protocol ID
- EER001
- Acronym
- PRESTO
- Status last verified
- Oct 2026
- First submitted
- 10 Sep 2014
- Last updated
- 3 Nov 2026
- Results posted
- No
- Data monitoring committee
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 3 Nov 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- PRe-operative ESTradiOl Window of Opportunity Study in Post-Menopausal Women With Newly Diagnosed ER Positive Breast Cancer
- ClinicalTrials.gov ID
- NCT02238808
- Acronym / sponsor ID
- PRESTO / EER001
- Conditions
- Estrogen Receptor Positive Breast Cancer
- Keywords
- ER+ breast cancer, Luminal A, Estradiol
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Active, not recruiting
- Enrolment
- 19 participants (actual)
- Lead sponsor
- AHS Cancer Control AlbertaUniversity, hospital or other
- Study start
- Aug 2015
- Primary completion
- 30 Jul 2018 (actual)
- Study completion
- Jun 2028 (estimated)
- First posted
- 12 Sep 2014 (estimated)
- 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.
Some breast cancers have estrogen receptors (ER+). The investigators know that some ER+ tumours can be cured by hormone therapy alone while other ER+ breast cancers cannot. Currently, there is no perfect way to tell these groups apart nor do the investigators know why some respond when others do not.
Research findings suggest that the two types of ER+ breast cancers differ in their response to estrogen with estrogen being toxic to one type and not the other. For those tumours that find estrogen toxic, this may explain why tumours only start to grow when estrogen levels decrease after menopause.
The purpose of this study is to see whether a two-week treatment of estrogen equal to pre-menopausal estrogen levels will decrease the rate at which patients' ER+ tumours grow. This will be done by comparing the growth rate in the tissue removed during standard of care surgery after patients have been treated with 7-14 days of estrogen prior to that surgery.
Detailed description
Breast cancer is a heterogeneous disease that includes two ER+ genetic subtypes (luminal A and luminal B) that differ in their response to treatment.
Results from the Women's Health Initiative Trial showed that estrogen treated hysterectomized women with no prior history of breast cancer had a significant and persistent decrease in breast cancer incidence when compared to placebo treated participants. This implies that some ER+ breast cancers are in fact growth inhibited by estrogens and are not growth promoted.
The hypothesis of this study is that some ER+ breast cancers (luminal A) are actually sensitive (growth inhibited) by estrogen.
Objectives:
- To assess changes in breast cancer proliferation after a 7-14 day trial of estradiol in newly diagnosed estrogen receptor positive post-menopausal breast cancer patients prior to surgery.
- Exploratory analysis of biologic correlates with comparison to available genotyping tests.
This is an open-label single group assignment pilot study for safety/efficacy and exploratory biologic correlates
Study design
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Estradiol treatment | Experimental | Drug: EstradiolEstradiol 6 mg daily for 7-14 days |
Who may qualify
- Ages
- 55 years and older
- Sex
- Female only
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (10 listed)
- Female gender
- Estrogen receptor positive (ER+) breast cancer
- HER2 negative breast cancer
- Post-menopausal by greater than 5 years
- No previous hormonal replacement therapy
Key exclusion criteria (11 listed)
- Pre-menopausal women
- Locally advanced or metastatic breast cancer
- Current, previous or planning for pre-operative treatment with chemotherapy, hormone therapy including corticosteroids, radiation therapy for malignancy or other condition
- Known hypersensitivity or intolerance to estradiol
- Ischemic changes on baseline electrocardiogram
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 |
|---|---|---|
| EstradiolAlso: estrogenEligible participants will take 2 mg Estradiol 3 times daily for 7-14 days pre-surgery. | Drug | Estradiol treatment |
Primary outcome
To assess changes in breast cancer proliferation after a 7-14 day trial of estradiol in newly diagnosed estrogen receptor positive post-menopausal breast cancer patients prior to surgery.
Time frame: end of 7-14 day treatment with estradiol
2 secondary outcomes
Exploratory analysis of biologic correlates with comparison to available genotyping tests
Time frame: end of 7-14 day treatment with estradiol
Analysis of recurrence/survival data based on initial Ki67 response to 7-14 day trial of estradiol.
Time frame: 10 years
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 3 Nov 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. This study is not recruiting at the moment.
Judith Hugh, MD principal investigator
University of Alberta
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 Estradiol in people with Estrogen Receptor Positive Breast Cancer, run by AHS Cancer Control Alberta at 1 site in Canada.
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 10 inclusion and 11 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: under way, not looking for participants, as of the sponsor's last update on 3 Nov 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 Canada. 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?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
To assess changes in breast cancer proliferation after a 7-14 day trial of estradiol in newly diagnosed estrogen receptor positive post-menopausal breast cancer patients prior to surgery. (time frame: end of 7-14 day treatment with estradiol). 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 3 Nov 2026.