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

NCT02238808 | Active Not Recruiting Phase 2

• 1 other identifier: EER001
• Study Type: interventional
• Target: 19
• Locations: 1 country
• Sites: 1

Brief 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. 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.

Conditions

Estrogen Receptor Positive Breast Cancer

Keywords

ER+ breast cancer; Luminal A; Estradiol

Outcome Measures

Primary Outcomes (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.

  end of 7-14 day treatment with estradiol

Secondary Outcomes (2)

• Exploratory analysis of biologic correlates with comparison to available genotyping tests

  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.

  10 years

Study Arms (1)

Estradiol treatment

EXPERIMENTAL

Estradiol 6 mg daily for 7-14 days

Drug: Estradiol

Interventions

Estradiol DRUG

Eligible participants will take 2 mg Estradiol 3 times daily for 7-14 days pre-surgery.

Also known as: estrogen

Estradiol treatment

Eligibility Criteria

• Age: 55 Years+
• Sex: female
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• 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

You may not qualify if:

• 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

Sponsors & Collaborators

• AHS Cancer Control Alberta: lead

Study Sites (1)

Cross Cancer Institute

Edmonton, Alberta, T6G 1Z2, Canada

Location

MeSH Terms

Interventions

Estradiol; Estrogens

Intervention Hierarchy (Ancestors)

Estrenes; Estranes; Steroids; Fused-Ring Compounds; Polycyclic Compounds; Estradiol Congeners; Gonadal Steroid Hormones; Gonadal Hormones; Hormones; Hormones, Hormone Substitutes, and Hormone Antagonists; Physiological Effects of Drugs; Pharmacologic Actions; Chemical Actions and Uses

Study Officials

• Judith Hugh, MD

  University of Alberta

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: phase 2
• Allocation: NA
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: September 10, 2014
• First Posted: September 12, 2014
• Study Start: August 1, 2015
• Primary Completion: July 30, 2018
• Study Completion (Estimated): June 1, 2028
• Last Updated: June 26, 2025

Record last verified: 2025-06

Data Sharing

• IPD Sharing: Will not share

Locations

CA (1)