A Study to See Whether Estrogen Can Slow the Growth of Some ER Positive Breast Cancers (PRESTO)

June 24, 2025 updated by: AHS Cancer Control Alberta

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.

Study Overview

Status

Active, not recruiting

Conditions

Intervention / Treatment

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:

  1. 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.
  2. 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 Type

Interventional

Enrollment (Actual)

19

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

  • Canada
    • Alberta
      • Edmonton, Alberta, Canada, T6G 1Z2
        • Cross Cancer Institute

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

55 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • 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
  • 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

Exclusion Criteria:

  • 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
  • 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

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: Treatment
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Estradiol treatment
Estradiol 6 mg daily for 7-14 days
Drug: Estradiol
Eligible participants will take 2 mg Estradiol 3 times daily for 7-14 days pre-surgery.
Other Names:
  • estrogen

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
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
end of 7-14 day treatment with estradiol

Secondary Outcome Measures

Outcome Measure
Time Frame
Exploratory analysis of biologic correlates with comparison to available genotyping tests
Time Frame: end of 7-14 day treatment with estradiol
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
10 years

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

AHS Cancer Control Alberta

Investigators

  • Principal Investigator: Judith Hugh, MD, University of Alberta

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

August 1, 2015

Primary Completion (Actual)

July 30, 2018

Study Completion (Estimated)

June 1, 2028

Study Registration Dates

First Submitted

September 10, 2014

First Submitted That Met QC Criteria

September 11, 2014

First Posted (Estimated)

September 12, 2014

Study Record Updates

Last Update Posted (Actual)

June 26, 2025

Last Update Submitted That Met QC Criteria

June 24, 2025

Last Verified

June 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • EER001

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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